Design Help for a New Guy

Fishermedic · April 2014

Well it's time for my first post here! I've been reading and following discussions on NAWS for a while and learnt a lot, it's great site!

Well here we go... This will be a long but hopefully entertaining read and I hope it will spark some conversation and debate!

I guess some background would help... We live in Geraldton, Ontario, the Great Canadian North!

My family and I (and 55+ other families) are living in the footprint of a proposed open pit mine. Over the last few years there has been a lot of exploration and talk about the possibility of this mine opening. Back in early January the mining company released its Preliminary Economic Assessment which provided a very positive report for the development of this open pit project. Since then we have received a little more information on the impact this has on the current residents within the mining area.... we all need to move!! Now the project isn't a done deal yet, there are still a number of hurdles for the mining company to clear... HOWEVER... things are moving forward for the affected property owners. We are now starting to move into negotiations with the company regarding our properties. We need a plan NOW! It's time to get going, they want to put a hole in the ground in 2 years!

So I've spent the last six months probably more reading, researching and learning about passive house design, passive solar design, mechanical systems, heating, electric, and solar and wind energy. I can't seem to find enough time in the day to read, research and learn as much as I want to!

So, with that out of the way, what am I looking to learn you ask? Well, property pickings are slim in Geraldton. There are currently 0 houses comparable to ours for sale, so we've been forced into planning to build a house. We've never thought about building a house until about a year ago and never thought seriously about it until last fall. At the same time we've been kind of changing the way we think about our impact on the environment lately and we've been trying to "go green" at least as much as we can little by little. So now that we're planning on building a house we have a huge opportunity to design a house as "green" as we can.

We are 95% committed to building a passive house, not a passive solar house, a passive house. The big difference is that a passive house focusses on air sealing and insulation to reduce heat loss and then uses passive solar gain (like a passive solar house would) to keep heat demands as low as possible. Lots of good info HERE.

We are probably 100% committed to solar PV in some form. Uhh, I guess "probably" means it's not 100% so lets say 99%. We don't have a building lot yet so off grid or grid tied are both still possibilities. If we're grid tied I think we'll end up going to the 10 kW max for Microfit. If we're off grid... well that's a whole different kettle of fish! I've looked at it and we'll see what happens with a building lot and the cost of running services to it. It would be a huge commitment for the family and a huge learning curve! The kids LOVE to stand in front of the fridge with the door open saying "There's nothing to eat!" and all 6 of them do it!! You'd think they'd learn by 16 but they don't! :roll:

Now on to the undecideds... is that a word?

With a passive house we'll still need supplemental heat, in the neighbourhood of 6400 HDD for Geraldton. At least we're not worried about cooling!

October to January are cloudy and dark, with panels at 50* (= to latitude) we have 3.1, 2.5, 2.8, 3.2 sun hours respectively. The end of December and all through January we see an average night time temp of -26 and an average high of -12. We also spend a good portion of our winter with the overnight low dipping to the -30 to -40 range, and not climbing much during the day. Just for fun the record low for Geraldton is -50.2 on Jan 31, 1996 and the next night was -49.3! Brrr.

So how do I heat 3000 sqft (or so) keeping in mind a passive house requires <15 kWh/(m2/yr) for heating and a heat load <10 W/m2? Typically a minisplit heat pump is used to provide heat in a passive house. The problem.... -40*, minisplits loose their production the colder it gets outside and by -20 they are pretty much useless. Unfortunate because they are very efficient. Geothermal radiant floor? Expensive and most likely very inefficient at the level of heat demand required by a passive house. Solar radiant floor? My main concern would be panels on my roof at -40, if they freeze I have a big problem! My first choice at the moment is a fireplace. Lots of firewood up here and possibly a few years worth just from clearing a lot to build! There are a few fireplaces that burn as cleanly as a wood stove and add a nice country farmhouse feel to a room. An open floor plan and a fireplace may do it and if I need to I can look at an inline heater for the ERV or electric baseboards for the bedrooms.

What about domestic water and hot water? This is where I've been spending most of my "learning time" lately. We would like to use rainwater harvesting for whatever we can, laundry, toilets, gardens, car washing...easy enough... but is it worth it to try to keep a large storage tank from freezing? I don't know yet! This winter our frost line got down to 8'-12' depending on where you were in town!

The bigger question is how do we heat our water in the most efficient way? What about preheating with solar and then using an electric water heater? Maybe a few extra PV panels to heat a largish storage tank which would feed into a smaller tank to bump it up to final temp for use. If the solar heated tank gets a little cool in the dark winter we still have the regular tank to keep us having warm showers and for most of the year that solar storage tank would provide the bulk of our hot water.

I think thats enough for now... some of you may have dozed off!

What I'm looking for now are ideas from those who've been there. What has and hasn't worked for you and what do you think about my, uhhh, plans?, ideas? I'm not sure what to call them at this point! haha. I'd love some feedback and ideas that may or may not work!

I'd like to take this thread through our planning process to a final design and then hopefully we can move to a "build thread"! We are looking to use as much renewable energy as possible in the most efficient way possible!

I'm looking forward to hearing your thoughts and ideas!

Bryan

mike95490 · April 2014

Re: Design Help for a New Guy

Be sure your building code allows a "passive house". We were thwarted by the requirement for Low-E windows registered by California. So we have minimal solar heat gain unless we open a window! Governmental idiots.

What does work (except for gumermint idiots again) is a Masonry Heater, a couple tons of brick and labyrinth flue that extracts the heat and stores it in the brick for a 15-24 hour release from each burn (I bring in 2 buckets ((5 gallon size)) of wood for each burn). We also have a SS thermosiphon water coil to a 80 gallon storage tank, for pre-heating our hot water. Summer we have a Rheem Solaraide for the water. So all year, we end up feeding our tankless water heater 90-140F water. You need propane for cooking anyway, and it's the most bang for the buck for water heating.

Masonry Heaters burn a load of wood for about 3 hours, full bore, glowing white hot inside. Then when the wood is nearly gone, you close the dampers to prevent air thermosiphon loss, and retain the heat in the masonry. The masonry never gets too hot to touch, and is a great warm room effect. It does require a open floor plan because it is radiant heat. Our 2nd floor runs in the low 60's, and the first floor right at 70F when we run the heater. It has a 2 day warm up, so you have to plan ahead. We burn between 3-4 cords of wood in Northern Calif. It would be half of that if we did not a gumermint mandated flue that stays 30% open.

And you will need to plan for a generator. You can bet that some of those 3 hour winter sun days will be cloudy. Perhaps Chris O. will chime in and comment on how he's made a thermostatically controlled generator shed to keep the crankcase oil from turning into goo when it's cold.

westbranch · April 2014

Re: Design Help for a New Guy

Mike s experience is similar to ours, just that we are not 'in' our house full time yet..

New High energy efficiency 'improvements' do not allow for using simple things like solar gain... in exchange you also will need an HVAC or similar system to suck power out of your batteries 24/7, so you can live in a 'plastic bag'. Plan in lots of opening windows that can use the normal wind patterns to vent excess heat from the house and provide some fresh air.
Our place, a timber frame. vaulted loft ceiling, has 8" double 2 x 4, offset framing, walls R28 of Roxul insulation and R40 high density foam ceiling insulation (R10 / inch) on top of an ICH 6" concrete basement (R50) ... it takes very little energy ( 5 light bulbs, 2 guys) to raise the basement winter temp from -6, inside, to +2 over 4 hours in 1000 Sq. ft! Upstairs is similarly energy efficient... If they require you to have a HVAC or ? just turn it off and manage the air manually... that's energy efficiency.

enjoy the ride...

Rybren · April 2014

Re: Design Help for a New Guy

I have nothing useful to add to what the other guys have already said.

I just wanted to say hi - I worked on the fire crews out of Beardmore/MacDiarmid in the latter half of the '70s, went to Con College in the Lakehead, flew bushplanes out of Armstrong for a guy from Nakina, and had a load of buddies from the Geraldton - Longlac area.

So... hi!

Jerry

Photowhit · April 2014

Re: Design Help for a New Guy

Sounds like 'fun'. Good luck!

If your grid tied and the Power Company allows for roll over, your golden, and just plan on electric water heating, and stove in my opinion. I heated a tin can (mobile home) with wood this last winter and was comfortable and burned less than 3 cords of wood, even with it's challenged insulation.

I'm off grid and heat my water as an opportunity load, though I have Midnite Classic Charge controllers I have yet to set them up to do this automatically. I think I could likely get by 95+% of the time on what I have up and running once I get this set up, but have choosen to experiment with what will be a hot water battery, I have another 2.5 Kw of panels and hope to set them up and run DC directly to the water heater and use the thermostat, so when available the array will send high voltage DC to the heater, the thermostat will act much as a charge controller when the water is cold it will allow it to heat, when hot it will shut off the flow of electric. This won't work with such a large family...

Fishermedic · April 2014

Re: Design Help for a New Guy

mike95490 wrote: »

Be sure your building code allows a "passive house". We were thwarted by the requirement for Low-E windows registered by California. So we have minimal solar heat gain unless we open a window! Governmental idiots.

What does work (except for gumermint idiots again) is a Masonry Heater, a couple tons of brick and labyrinth flue that extracts the heat and stores it in the brick for a 15-24 hour release from each burn (I bring in 2 buckets ((5 gallon size)) of wood for each burn). We also have a SS thermosiphon water coil to a 80 gallon storage tank, for pre-heating our hot water. Summer we have a Rheem Solaraide for the water. So all year, we end up feeding our tankless water heater 90-140F water. You need propane for cooking anyway, and it's the most bang for the buck for water heating.

Masonry Heaters burn a load of wood for about 3 hours, full bore, glowing white hot inside. Then when the wood is nearly gone, you close the dampers to prevent air thermosiphon loss, and retain the heat in the masonry. The masonry never gets too hot to touch, and is a great warm room effect. It does require a open floor plan because it is radiant heat. Our 2nd floor runs in the low 60's, and the first floor right at 70F when we run the heater. It has a 2 day warm up, so you have to plan ahead. We burn between 3-4 cords of wood in Northern Calif. It would be half of that if we did not a gumermint mandated flue that stays 30% open.

And you will need to plan for a generator. You can bet that some of those 3 hour winter sun days will be cloudy. Perhaps Chris O. will chime in and comment on how he's made a thermostatically controlled generator shed to keep the crankcase oil from turning into goo when it's cold.

I haven't looked into the specific codes but there are a number of passive houses already built in Southern Ontario, same province but 12 to 18 hours drive from us and a heck of a lot warmer! I'm hoping there won't be any issues with a passive house and if there are they should be easily overcome. I started out maybe at the end of last summer knowing nothing at all about solar, renewable energy, passive house, passive solar, water heating, HVAC... nothing! I thought a windmill would be great for when it was stormy and solar panels for when it wasn't, we were never going to pay for electricity again! LOL I've come a long way but I still don't know much, especially about things like building codes.

I had run across masonry heaters a while back but didn't get into them too much. The closest city to us us is 3 hrs away and the closest dealer for a masonry heater is closer to 14 I think. I did go back to look at them from your link though and realised that the guts of the system are completely separate from the stone work. So I should be able to ship the fire box and have a mason from the city do the stone work. It's definitely worth revisiting. As you said the benefits of the thermal mass in a passive house would be great.

I'm assuming you have the thermosiphon worked into the heater? I'm not sure how much benefit I'd realise from that setup since I hope to need to burn very little during the winter but boy would that be great to have in the house we're in now! We've got a wood burning forced air furnace that's always got a fire on!

How long have you had the Solaraide? Have you had any maintenance or trouble with it? I also have seen a few times that it would be more cost effective to heat water with PV over evacuated tube or flat plate collectors (did I get those right?

). Any thoughts on this?

Thanks for the reply, this is the kind of info I was hoping for!

Bryan

Fishermedic · April 2014

Re: Design Help for a New Guy

westbranch wrote: »

Mike s experience is similar to ours, just that we are not 'in' our house full time yet..

New High energy efficiency 'improvements' do not allow for using simple things like solar gain... in exchange you also will need an HVAC or similar system to suck power out of your batteries 24/7, so you can live in a 'plastic bag'. Plan in lots of opening windows that can use the normal wind patterns to vent excess heat from the house and provide some fresh air.
Our place, a timber frame. vaulted loft ceiling, has 8" double 2 x 4, offset framing, walls R28 of Roxul insulation and R40 high density foam ceiling insulation (R10 / inch) on top of an ICH 6" concrete basement (R50) ... it takes very little energy ( 5 light bulbs, 2 guys) to raise the basement winter temp from -6, inside, to +2 over 4 hours in 1000 Sq. ft! Upstairs is similarly energy efficient... If they require you to have a HVAC or ? just turn it off and manage the air manually... that's energy efficiency.

enjoy the ride...

I'm not sure I understand your position but...
I gather you are not convinced that an airtight home with an HRV or ERV will provide you with the comfort you desire? Or is it a matter of having to run an HRV 24/7 off grid?

I firmly believe that if the house is designed properly, (meaning south glazing sized to provide the heat we need and minimise overheating with a sufficient amount of thermal mass and insulation) and sealed extremely well it will be comfortable year round. I understand the issue of running an HRV 24/7 when you're off grid when an open window will provide fresh air with zero power usage. I'm a big fan of open windows and for the warmer months that would our means of cooling. However, I do want to keep as much of the heat we generate inside the house during the colder months, so opening windows when we're heating doesn't seem like the best idea. Now if our heat is coming solely form solar gain (in the shoulder seasons) and it's warm enough in the house you bet we'll be opening windows but the less money we throw out those windows the better.

Bryan

Fishermedic · April 2014

Re: Design Help for a New Guy

Rybren wrote: »

I have nothing useful to add to what the other guys have already said.

I just wanted to say hi - I worked on the fire crews out of Beardmore/MacDiarmid in the latter half of the '70s, went to Con College in the Lakehead, flew bushplanes out of Armstrong for a guy from Nakina, and had a load of buddies from the Geraldton - Longlac area.

So... hi!

Jerry

Small world, my wifes family is in Ottawa, Gatineau and the Pontiac and my Dad's in Montreal. We visit quite a bit.

Photowhit wrote: »

Sounds like 'fun'. Good luck!

If your grid tied and the Power Company allows for roll over, your golden, and just plan on electric water heating, and stove in my opinion. I heated a tin can (mobile home) with wood this last winter and was comfortable and burned less than 3 cords of wood, even with it's challenged insulation.

I'm off grid and heat my water as an opportunity load, though I have Midnite Classic Charge controllers I have yet to set them up to do this automatically. I think I could likely get by 95+% of the time on what I have up and running once I get this set up, but have choosen to experiment with what will be a hot water battery, I have another 2.5 Kw of panels and hope to set them up and run DC directly to the water heater and use the thermostat, so when available the array will send high voltage DC to the heater, the thermostat will act much as a charge controller when the water is cold it will allow it to heat, when hot it will shut off the flow of electric. This won't work with such a large family...

Ya the family size makes EVERYTHING more of a challenge. Transportation for 8 isn't easy never mind trying to learn how to design an efficient home in the middle of nowhere!

I'm always impressed to see guys living off the land so to speak. There's a lot to be said for a simpler life!

BB. · April 2014

Re: Design Help for a New Guy

I too am a bit ambivalent because of some of the issues with "sealed homes" and geothermal systems.

Both systems can require a fair amount of power to operate (the heat recovery ventilator, a few hundred Watt motor running 12-24 hours per day(?). And the water circulation pump for the geothermal can be another 1,000-2,000 watts running 24x7 (worst case?) during the max heating/cooling seasons).

Add that the kids will start moving out in 1-2 decades--Leaves you with a large home (and possibly high power costs) with few people there to justify the costs.

Do the paper designs first--Before you buy any hardware, and possibly before you purchase any land (near utility power or not). In general, living off the grid is a constant battle with conservation (minimum power usage vs "the kids" and spouse). And while you can certainly build out an off grid power system that will run "anything"--Large systems cost a lot of money to install/maintain, and you still will probably have a good size fuel bill (especially during winter) to run everything.

Gasoline is just hitting $4+ per gallon in our area--And with the present governmental policies, I fear that this may be the price floor for the next few years (at least).

Depending on the eventual use of your property in the future (make the home a bed and breakfast for summer/winter visitors--Or possibly selling/renting out main home and living in a cabin off to the side)--All needs to be considered.

As you have seen, off grid solar power is not cheap. A rough rule of thumb for solar electric is ~$1-$2+ per kWH vs the $0.10-$0.20+ per kWH for "city power". If you looked at your power as being 10x the price of what you are paying today--What would you "do different" with your new home.

Also, here is a FAQ thread with lots of links/information for various off grid/conservation projects... See if there is anything of interest for you (particularly thermal solar systems as used in colder climates).

Off grid power is expensive--Look closely before you leap. Add that batteries need replacement every ~5-10 years (with today's lead acid technology), electronics need replacement ~10+ years (inverters, charge controllers, etc.)--And your abilities (and spouse/family) a few decades down the road--It can make for some sleepless nights.

-Bill

Blackcherry04 · April 2014

Re: Design Help for a New Guy

Since you mentioned Mini Split Heat Pump, do your research, while they have made great strides in nibbling around of the edge of the Refrigeration they cannot change the physics of it. While they can produce some heat and that shows in the COP, anything below 5 degrees or so is useless to try to heat a house with. Once you look at the power consumption below 17 deg you see thy have added a heat strip because the compressor is less than 50% output.

Attachment not found.

westbranch · April 2014

Re: Design Help for a New Guy

HI, my thoughts are I no longer wish to be living inside a plastic bag.....

I worked in several offices in that style of construction over my 'work' life, spoke with the engineers that designed them if I had a chance and, at the time, thought they were state of the art, until the problems started showing up... like the control systems were in another city and at -30C outside we had inside temps of 10C, BUT the system said it was 20C inside, Not! plus in summer there was one opening window, in the coffee room, if left open, the call would come to shut it , it was interfering with the A/C......another building I was in supposedly got 10% makeup air, 15 years later they discovered the intake had been bricked over ??? Then the UBC says, hermetically seal your building to save energy, but it takes more energy. A friends HVAC on Low speed,uses 1 Kwh per day, 2 years old now, Off Grid that is too much to expend just for fresh air IMHO...
I know, I'm biased...
YMMV

mike95490 · April 2014

Re: Design Help for a New Guy

I'd forgotten about the vent fan that was hardwired in, and now just has a switch. County wanted 24/7 fresh air.

Lee Dodge · April 2014

Re: Design Help for a New Guy

Bryan-

Some of the guys on this forum do not seem to be so familiar with Passive House design. This forum is a good place for a discussion of the solar stuff, but for discussion of the Passive House design, you might try http://www.greenbuildingtalk.com/Forums.aspx.

I was interested in modifying a standard production house design to approach or meet net-zero source energy with a minimum investment, and I was able to meet my goals as described at http://www.residentialenergylaboratory.com/rel_description.html. However, that is an easier goal to achieve here than at your location, since our solar insolation on a flat plate angled at the latitude is 5.78 kW/m^2/day here versus about 4.5 kW/m^2/day at Thunder Bay, which I assume might be similar to your location. If your solar insolation is that high, that would be a fair amount of energy to work with. We have about 7000 heating degF days here, so about 3890 heating degC days, so only 61% of what you have.

In my location, I found that some of the Passive House standards could not be economically justified, such as the maximum infiltration rate of 0.6 air changes per hour (ACH) at 50 kPa differential, and the insulation levels under the foundation. I have an infiltration rate of 2.4 ACH, and in this area they use conditioned crawl spaces, and my calculation showed that 1" of XPS (R-5) plus several feet of mostly sand between the bottom of the crawl space and the outside air provided a minimum overall insulation level similar to the walls, which are about R-28. In my case, it was better to spend the money on solar PV and solar domestic hot water than to follow the Passive House guidelines. The computer model BEopt is helpful in trading off more insulation versus solar PV.

Some of the comments on this forum indicated that folks could not get low-e windows with high solar gain. I chose some triple-pane. low-e windows that met the maximum U-value code, and were also high solar gain. They work well for passive solar gain in this climate. Window regulations in Canada tend to favor the high solar gain windows anyway, so you should not have the same problems that some folks have in the U.S. with window codes. High solar gain windows would likely be important at your latitude (http://www.residentialenergylaboratory.com/window_codes.html).

Discussions on this forum indicate that grid-tie PV systems are much more cost efficient that off-grid systems, so if the grid is available, consider connecting to the grid. I have a grid-tie system, and it has been completely maintenance free since installation four years ago.

Good luck on your adventure.

Cariboocoot · April 2014

Re: Design Help for a New Guy

Actually the comments have been more along the line of "beware the local regulations" rather than "we don't know anything about this stuff".

Those local regs can trip you up every time. No matter how good the idea is, how well designed, or how proven in other jurisdictions if the AHJ says "no" that's the end of it unless you like long and expensive court cases. :roll:

Rybren · April 2014

Re: Design Help for a New Guy

Fishermedic wrote: »

Small world, my wifes family is in Ottawa, Gatineau and the Pontiac and my Dad's in Montreal. We visit quite a bit.

My off-grid camp and solar system is in the Pontiac. We'll have to touch base some time.

Fishermedic · April 2014

Re: Design Help for a New Guy

BB. wrote: »

I too am a bit ambivalent because of some of the issues with "sealed homes" and geothermal systems.

Both systems can require a fair amount of power to operate (the heat recovery ventilator, a few hundred Watt motor running 12-24 hours per day(?). And the water circulation pump for the geothermal can be another 1,000-2,000 watts running 24x7 (worst case?) during the max heating/cooling seasons).

Geothermal was what I thought we'd do when we started looking into this. After some reading I quickly found out the pump was a huge draw. Our last electric bill was $175, 776kWh for the month. The breakdown is about $70 for the electricity and $105 for fees and delivery. I hate getting that bill, it's doubled since we moved into the house and keeps rising. So HRV's are not overly popular here, I understand why if you have reasonable winter temps. If you can open a window for some fresh air without having to put a parka on why would you want to use the energy to run an HRV. However at -40 the windows stay closed (probably because they're frozen haha) and when the front door is open you don't want to be close with just a housecoat on! So is it better to keep the heat you've already generated and run an HRV (at under 100W) or heat the fresh air you bring in and loose the heat you've already made?

Add that the kids will start moving out in 1-2 decades--Leaves you with a large home (and possibly high power costs) with few people there to justify the costs.

Well this is something we're putting a lot of thought into, we have a big family, 6 kids and two dogs, we already have two per bedroom and at around 3800 sqft there's enough room for us to be comfortable. We are looking for ways to make a smaller house function just as well not only for after the kids leave but because a smaller house will cost less to run and also be easier to clean and maintain.

Do the paper designs first--Before you buy any hardware, and possibly before you purchase any land (near utility power or not). In general, living off the grid is a constant battle with conservation (minimum power usage vs "the kids" and spouse). And while you can certainly build out an off grid power system that will run "anything"--Large systems cost a lot of money to install/maintain, and you still will probably have a good size fuel bill (especially during winter) to run everything.

Gasoline is just hitting $4+ per gallon in our area--And with the present governmental policies, I fear that this may be the price floor for the next few years (at least).

If there's anything I've learned from this site it's to plan, design and plan some more, then repeat, before spending a dime! That's why I started the thread, it's time to start talking dollars and cents with the company that's going to write the cheque, that means I need to start making decisions soon.

Oh and fuel prices in my neck of the woods... $5.69 a gallon for regular and diesel is $5.85. $4 would be nice to see!

Depending on the eventual use of your property in the future (make the home a bed and breakfast for summer/winter visitors--Or possibly selling/renting out main home and living in a cabin off to the side)--All needs to be considered.

As you have seen, off grid solar power is not cheap. A rough rule of thumb for solar electric is ~$1-$2+ per kWH vs the $0.10-$0.20+ per kWH for "city power". If you looked at your power as being 10x the price of what you are paying today--What would you "do different" with your new home.

Also, here is a FAQ thread with lots of links/information for various off grid/conservation projects... See if there is anything of interest for you (particularly thermal solar systems as used in colder climates).

Off grid power is expensive--Look closely before you leap. Add that batteries need replacement every ~5-10 years (with today's lead acid technology), electronics need replacement ~10+ years (inverters, charge controllers, etc.)--And your abilities (and spouse/family) a few decades down the road--It can make for some sleepless nights.

-Bill

I think the long range plan is to build and live in the house until retirement (25 years or so) and then sell. We don't have any desire to retire here, for a number of reasons, and the house will be too big for just the two of us. Ideally we'll sell and move someplace warmer and closer to a city hospital. Plans change though so who knows what will happen.

As for grid or off grid, it's still very much up in the air. Right now we're paying $0.225 per kWh average (from the last bill) and it's not going to stop increasing. Once we have a property and budget we'll do some calculations and see which one makes more sense. I'm not sure what the cut off for off grid will be but my wife and I would both love to be rid of the electricity bill for good.

Bryan

BB. · April 2014

Re: Design Help for a New Guy

I understand the need for an HRV in extreme climates--As long as you add that to your power calculations, they are OK and better than heating/cooling "extra" outside air.

In general, I don't see the off grid system as an "investment" that the next buyer will pay much for... So, spend what makes sense for your needs and don't "over-invest" in your power plant (expensive to maintain and not worth very much to the eventual buyers).

-Bill

Fishermedic · April 2014

Re: Design Help for a New Guy

So where am I at now? We're going to see how far our budget gets us towards the passive house standard while we continuously check the price vs payback of meeting that standard. Maybe our best bet for heat is a masonry heater, geothermal was out a long time ago and mini splits don't work when it's cold out. PV is still definitely in, the grid tie off grid debate will start when we get a better idea of the cost to service a lot and an idea of where that lot will be.

Now hot water... Maybe just plain old ordinary electric powered by PV and drain water heat recovery? I wonder...

What other options are out there? What do others do to increase the efficiency in the home and decrease their operating cost?

Fishermedic · April 2014

Re: Design Help for a New Guy

Ya I've seen mention of an off grid system not being an investment a few times. I guess with the price of solar dropping so fast over the last few years the panels you bought for $7 a watt are worth less than $1 a watt now since they can be replaced for that price.

I've learned another great little lesson here... Whether it's designing a house, a power system, or just living life it's all about finding the right balance.

westbranch · April 2014

Re: Design Help for a New Guy

So is it better to keep the heat you've already generated and run an HRV (at under 100W) or heat the fresh air you bring in and loose the heat you've already made?

Well we decided on a well insulated 'entry porch' that will be like an air lock to prevent 'reallly cold- 40C air' from having a direct shot to the wood stove.

IMO spend money on more insulation to minimize the amount needed for making heat (oil, propane, ? or wood) and avoid spending 2.4Kwh of $$ on an HVR daily...

Lee Dodge · April 2014

Re: Design Help for a New Guy

IMO spend money on more insulation to minimize the amount needed for making heat (oil, propane, ? or wood) and avoid spending 2.4Kwh of $$ on an HVR daily

The HRV that I have uses 28 W on low and 71 W on high (measured with Kill-A-Watt), so daily energy use for full-time operation would be 0.7 kWh on low and 1.7 kWh on high. Details are given here. HRVs with ECM motors tend to be the most efficient. In a house with eight people, an HRV might be handy to control indoor humidity and avoid CO2 buildup.

The two items with the shortest payback times in my new construction (2010) house were high solar gain windows (they normally install low solar gain windows here to meet the maximum allowed U-value spec.), and the solar PV system. Code minimum houses are fairly well insulated here, but I added more insulation on top of code minimum. Details are given here. Electric bills beyond the connection fee of ~$6.45/month average zero, and natural gas (for space heat, domestic hot water, and cooking) bills beyond the connection fee of ~$11.48/month average $182.54 annually or $15.21 monthly.

Cariboocoot · April 2014

Re: Design Help for a New Guy

Lee Dodge;

How's the weather there in Colorado? What kind of highs/lows do you experience?

solar_dave · April 2014

Re: Design Help for a New Guy

And Lee your connection fees are dirt cheap.

Lee Dodge · April 2014

Re: Design Help for a New Guy

Cariboocoot wrote: »

Lee Dodge;

How's the weather there in Colorado? What kind of highs/lows do you experience?

I am in a valley next to the continental divide at an elevation of about 7100' (2329 m), so the weather here is not "typical" for Colorado. Since Colorado is so mountainous, all weather is local. The heating degree days in my town average 7049 (degF), so 3916 (deg C), for a base temperature of 65F (18.3C). Cooling degree days are 104 (degF), so 57.8 (degC), again for a base temperature of 65 F (18.3C). I do not need or have A/C, since a well-insulated house can hold the cool night air through a summer day. The actual heating degree days for the years that I have been here are lower than the historical average, and are provided in the plots here.

Record lows and highs in Salida are -33 F (-36 C) and 103 F (39 C).

Lee Dodge · April 2014

Re: Design Help for a New Guy

solar_dave wrote: »

And Lee your connection fees are dirt cheap.

Is this something that I should complain about?

Cariboocoot · April 2014

Re: Design Help for a New Guy

Not too different from our wonderful Cariboo climate with its 80 degree Celsius temperature swing between Winter and Summer. (We don't actually have Spring or Fall.)

BB. · April 2014

Re: Design Help for a New Guy

That looks like a nice HRV Lee... Only 50-70 CFM from a single ventilator on low (rated 50-200 CFM?) is enough for a good size home (upwards of 3,000 SqFt)?

-Bill

Lee Dodge · April 2014

Re: Design Help for a New Guy

BB. wrote: »

That looks like a nice HRV Lee... Only 50-70 CFM from a single ventilator on low (rated 50-200 CFM?) is enough for a good size home (upwards of 3,000 SqFt)?

-Bill

Ventilation is used to accomplish a number of things in a home including:

- Remove humidity created from showers, cooking, etc.
- Remove contaminants from household items like volatile organic fraction (VOF) from floor finishes, plastics, paints, adhesives, etc.
- Remove contaminant from human activities like CO2 from breathing, fireplace smoke, fingernail polish, adhesives, passing gas, bathroom odors, etc.
- Remove contaminants from cooking including both combustion products from natural gas and food odors.
- Remove radon gas in those areas where radon is a problem.

Obviously the ventilation requirements might vary with the use of individual ventilation devices such as bathroom and kitchen stove exhaust fans, habits of the residents, and the house construction. This problem has been addressed in ASHRAE 62.2-2007, which specifies whole-house ventilation at the rate of ([number of bedrooms + 1] times 7.5 cfm plus [0.01 cfm/ft2 of conditioned space]) cfm. I have performed some example calculations:

Floor area sq ft 1000 1500 2000 3000
First floor wall height ft 8 8 8 8
Volume cu ft 8000 12000 16000 24000
Number of bedrooms 3 3 4 5
Number of inhabitants 3 3 4 4

The minimum ventilation requirements for the 1000, 1500, 2000, and 3000 sq. ft. homes are 40, 45, 58, and 75 cfm, respectively, according to this standard. So on my particular HRV, these requirements could be met using the low speed operation that requires 28W of electrical energy.

BB. · April 2014

Re: Design Help for a New Guy

Lee,

That is what I was seeing--At 28 Watts, that is a reasonable amount of power. I was thinking it was going to be 100-200 watts or more for an HRV.

-Bill

solar_dave · April 2014

Re: Design Help for a New Guy

Lee Dodge wrote: »

Is this something that I should complain about?

No but it should be something I can whine about! LOL

Fishermedic · April 2014

Re: Design Help for a New Guy

westbranch wrote: »

So is it better to keep the heat you've already generated and run an HRV (at under 100W) or heat the fresh air you bring in and loose the heat you've already made?

Well we decided on a well insulated 'entry porch' that will be like an air lock to prevent 'reallly cold- 40C air' from having a direct shot to the wood stove.

IMO spend money on more insulation to minimize the amount needed for making heat (oil, propane, ? or wood) and avoid spending 2.4Kwh of $$ on an HVR daily...

There's another really good point for the "extreme climate" folk. Airlock entries are a big deal. Imagine 5 kids heading out the door for the school bus when the wind is blowing straight in the front door and the windchill is -45. One of my first design requirements was an airlock for all entries. All I think when the kids are leaving is "Hurry up and close the door! It's f'in cold out there and I need to heat all that cold air you're letting in!".

Design Help for a New Guy

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