Tiny House Solar Config

Steven Lake · January 2012

Hi again all. It's been a while, but given how crazy the last two months were, it's understandable. Anyhow, I've got another question for you, since I'm still a learning beginner here. I was looking at this video up on Youtube about what I believe to be the single best designed Tiny House ever. It's 320sqft and runs only a handful of basic appliances. My guess is that they don't use much power at all, even though they've got mainstream appliances.

In your best opinion (no, I don't have one of these houses, but I'm highly considering it), what would you say would be required to run a house like this on solar? I'm guessing 500ah of battery, about 2000w max inverter, and 6x180w solar panels. But that's my guess. Now obviously I'd make the heat propane, and use camper appliances of the same size instead of the stuff they have to save on power. Even so I'm wondering what your thoughts would be on the required power and setup to run one. At only $3500 to build one of these, and another $2k to outfit it with a decent list of creature comforts, it'd leave plenty of extra cash (assuming your budget is $20k) for a solar setup.

Anyhow, what's your thoughts? The two designs I was thinking was a completely off grid power system, and a basic light weight solar to power just the basics. (ie, fridge and some basic lighting.) My primary interest in asking is I'm thinking of building one for a camper of sorts. Since it works just as well, and costs just a fraction of a good camper (plus you can adjust and reconfigure it down the road) and can go anywhere a camper can go.

Cariboocoot · January 2012

Re: Tiny House Solar Config

Without even looking at the video ...
I have 320 Amp hours @ 24 Volts and 700 Watts of panel with a 3.5 kW inverter. About 2.4 kW hours per day.
This runs a 1200 sq. ft. "house" (cabin) with all creature comforts including running water in/out (needs a septic pump) electric refrigerator, computer set-up, microwave oven, lights, et cetera. Pretty much anything you'd want providing you pay attention to available power and usage. I did an "updated design" a little while back based on equipment available now and found I could get a noticeable increase in power but basically the same system for about $6,000, self-installed.

This would vary depending on your particular building site. That matters more than the size of the structure when it comes to electrical use. Solar installs are highly site specific.

Photowhit · January 2012

Re: Tiny House Solar Config

If you haven't lived in a small place try it first, If you haven't live on solar or a budgeted power usage try it first.

I do not know where you live or your personality, but there is a lot to learn and some of it must be experienced. Heating and cooling is not done easily with solar. The house in the video is NOT setup to run on solar. If your planning to live in your tiny house check local regulations, most have a minimum square footage of 500+.

All that said, I have lived in a 10x16 cabin(w/sleeping loft) and a seperate 8x10ish kitchen and bath, that I built in central Missouri.
Attachment not found.
To cool the cabin with a window AC I built it with 6" thick walls and built it in the shade. I was able to use the AC for 3-4 hours a night with a 24v string of 6 volt golf cart batteries. I could run the AC a bit during the day after the batteries were topped off. I started with a 1000 watt array and grew it to 2000 watts over 4 years. I also ran a small fridge, microwave and a toaster oven (at times when I had little demand) Most of the cooking was done with gas, all the heating was done with gas. The batteries is/was the limiting factor with a 2000 watt array. I didn't try it since I replaced the small string with a large traction battery as I found a piece of property w/a modular home that I wanted to purchase. I suspect with my highly effeicence cabin I might have been able to run around the clock on other than cloudy days

The seperate bath and kitchen is for the solar consideration, you don't want to cook where you need to cool, You basically don't run a frost free fridge on solar as they way they keep frost free to work against the cooling, not effiecent. I clothes lines is your dryer on solar(though you could use gas)Sleeping lofts are fine in the winter so long as the person needing the most warmth sleeps there, but there will be a somewhat large temperature difference. In the summer, even and open loft tends to be warm even running fans.

Your perspective will be different depending on where you move from. I had recently spent most of a year bicycling living out of a tent;
Attachment not found.
I was use to the confined quarters, and I had been living on 200watt array and 2 golf cart batteries, with just a couple fans in the summer, no fridge laptop, compact floresent lights and and MP3 player, so this cabin was somewhat a luxury.

The video paints a rosy picture, but did you see the bed up against a door? So I say move into a camper for a couple months, limit your electrical use to 1Kw a day for a while see what you can deal with, there will be some adjusting.

Slappy · January 2012

Re: Tiny House Solar Config

you might be interested in this vid. http://www.youtube.com/watch?v=fJsDOD0dTQI&feature=relmfu

icarus · January 2012

Re: Tiny House Solar Config

We live in ~600 sq ft.. We have all thcomfortw of home, including hot and cold water, full lights, sat ISP, stero etc. (no TV, but we do have two lap tops most all most days.). We uses propane for the fridge and the kitchen, hot water etc.

We have 400 WH tts of PV. On a daily basis, we use ~ 5-800 watt/hours of power. On an averge day, we generate just about the same,, on an ideal day, we can generate nearly 2 kwh. We have 450 ah of T-105 batteries, configured to 12 vdc, and we use a Shursine 300 inverter for all AC loads.

We run a number of w12 vdc loads, including some lighting, radio phone, stereo, sat radio,paddle fans as well as fridge fans etc. if I had to do it over again, I would add a UN mover of panels, and consider a good conventional fridge instead of the propane. Propane is mi ch cheaper in toto when a house or cabin is used on weekends and thocasional holiday week. The more it gets used, the cheaper the net cost of a conventional fridge and the PV to run it?

Tony

Volvo Farmer · January 2012

Re: Tiny House Solar Config

At the risk of dragging this topic in a specific direction, I disagree with Photowit about frost free refrigerators. It's quite amazing how efficient conventional frost-free refrigerators have gotten in the last five or six years.

Here is a 9.7 CF GE manual defrost refrigerator that uses 338 KWhr/yr
http://products.geappliances.com/MarketingObjectRetrieval/Dispatcher?RequestType=PDF&Name=GMS10AAR.pdf

Here is a 18 CF GE frost free refrigerator which uses 311 KWhr/year
http://www.homedepot.com/catalog/pdfImages/c0/c03bf95d-7768-4dfd-9ba0-53c8af08559c.pdf

Tony has hit the nail on the head. With refrigerators that use less than a kwhr/day available for less than $500, and solar panels available for less than $1.50 a watt, I think the payback would be on the order of months rather than years if one were to choose a $500 conventional refrigerator over a $1000 propane one.

We have a little 8CF propane refrigerator downstairs and it uses a gallon of propane every 4 days. At $2/gallon it costs $15/month to run the thing. If you have enough battery to get you through 500whr overnight, an electric refrigerator and extra panels are a no-brainer.

waynefromnscanada · January 2012

Re: Tiny House Solar Config

Volvo Farmer wrote: »

We have a little 8CF propane refrigerator downstairs and it uses a gallon of propane every 4 days. At $2/gallon it costs $15/month to run the thing. If you have enough battery to get you through 500whr overnight, an electric refrigerator and extra panels are a no-brainer.

You've got it easy. lol Here a refill on a "20 pound" propane cylinder is reaching for $30.00 and will last about one week on a little 8 Cu Ft fridge. That's almost $120.00/month to run the thing, and LPG costs are going up all the time

icarus · January 2012

Re: Tiny House Solar Config

The last taanks I had filled last fall, cost me about $80 CDN for a 100#, or ~ 20 gallons net. I'm guessing when I refill in the spring it will be closer to $100.

T.

Photowhit · January 2012

Re: Tiny House Solar Config

Volvo farmer(how many do you get per acre?) I'll have to look into this, my base is 6-7 years old surprised it's that low.

Is that a refill or exchange? It was $14 for a refill in central Missouri, Exchanges are a rip off at $18-26 for a 3/4 fill, They only put 15lbs in the Exchanges.Maybe Canada has some extra taxes on propane...

waynefromnscanada wrote: »

You've got it easy. lol Here a refill on a "20 pound" propane cylinder is reaching for $30.00 and will last about one week on a little 8 Cu Ft fridge. That's almost $120.00/month to run the thing, and LPG costs are going up all the time

solarvic · January 2012

Re: Tiny House Solar Config

Times sure have changed. In the early 70,s I paid $8.00 per 100 lb. tank delivered connected to line and they took back the empty tank. :Dsolarvic:D

icarus · January 2012

Re: Tiny House Solar Config

Photowhit wrote: »

Volvo farmer(how many do you get per acre?) I'll have to look into this, my base is 6-7 years old surprised it's that low.

Is that a refill or exchange? It was $14 for a refill in central Missouri, Exchanges are a rip off at $18-26 for a 3/4 fill, They only put 15lbs in the Exchanges.Maybe Canada has some extra taxes on propane...

Remember we are talking out 100# not 20# tanks.

I also remember when diesel was $.11, and regular gas was $.30

Tony

Volvo Farmer · January 2012

Re: Tiny House Solar Config

I have never actually measured the consumption of our frig. I found a specification online that said it used 1 lb a day, and that there were approximately 4 lbs/gallon of propane. Are you folks really living on 20 and 100 lb tanks? We found a used 250 gallon tank for $200 and a truck comes out and fills it when it gets low. I just paid $2.15/gallon this weekend to have the tank filled. The bill was over $400 but we will get several months out of it.

Also, our main frig is a $500 Kenmore that uses about 1.2 Kwhr a day and it was the most efficient reasonably priced one I could find three years ago. I have put the kill-a-watt on ours and the Energyguide numbers are accurate. I'm seriously thinking about getting one of these new GE units as they are at least 25% more efficient than what I bought.

icarus · January 2012

Re: Tiny House Solar Config

A full sized automatic Dometic will burn ~1500 BTUs per hour,, with. Duty cycle between ~33 and 66%. So a gallon of propane holds ~79,000 BTUs. Buring full bore it will burn about 52 hours per gallon, 104 with a 50% duty cycle.

We use 100 (60#) tank because we are 150 kmsfrom town, up a bush road,, and then 15 Kim's down the lake. No delivery possible. My neighbor an I pool our resources, and who ever is going to town will haul tanks as needed, for refill.

Tony

vcallaway · January 2012

Re: Tiny House Solar Config

Typically delivery has some type of minimum. Usually that gets you the best price as well. Do some research before deciding.

We are spending the winter in our motorhome. Last summer we opted to change out our propane refrigerator with an electric unit. The one we use is a Whirlpool 9.6 cu ft model. The savings over going with a new propane unit paid for the solar install plus some.

This refrigerator uses less than 1kw per day. It draws about 100w while running. It works so much better than the propane units and has more room inside. Best decision we made in our remodel.

I've looked at those tiny houses. We have thought about building one as a guest house. They don't work for me mostly because I'm not a tiny person

A design we liked is based on a Yurt. A round house with a peaked roof. Made the most sense for the climate in the PNW.

vtmaps · January 2012

Re: Tiny House Solar Config

icarus wrote: »

So a gallon of propane holds ~79,000 BTUs.

that's unfortunate that you get so few BTU per gallon. The US Dept. of Energy says we get 91,330 BTU per gallon propane. The American Gas Association says 91,600 BTU.

Are we talking about the same gallon? I thought Canadian gallons were bigger and had even more BTU.
--vtMaps

BB. · January 2012

Re: Tiny House Solar Config

Regarding Yurts and other non-square/traditional homes... Many times there is a waste of space/difficulty with furniture/other stuff trying to place it in these types of home.

At least in US/western culture, our stuff is rectangular/square and does not fit well with round walls.

-Bill

BB. · January 2012

Re: Tiny House Solar Config

By the way, here is a nice little Propane/Butane/Mix chart of the properties:

http://www.altenergy.com/downloads/pdf_public/propdatapdf.pdf

-Bill

Volvo Farmer · January 2012

Re: Tiny House Solar Config

vcallaway wrote:

Typically delivery has some type of minimum. Usually that gets you the best price as well. Do some research before deciding.

We are spending the winter in our motorhome. Last summer we opted to change out our propane refrigerator with an electric unit. The one we use is a Whirlpool 9.6 cu ft model. The savings over going with a new propane unit paid for the solar install plus some.

This refrigerator uses less than 1kw per day. It draws about 100w while running. It works so much better than the propane units and has more room inside. Best decision we made in our remodel.

Hmm, the energy guide shows it uses 1.15 KWhr a day. Did you actually measure yours? I've never heard of people beating the energyguide numbers by 20% unless the frig was in a very cold ambient temperature.

vcallaway · January 2012

Re: Tiny House Solar Config

Used the old old kill-o-watt the test it. The couple of times I tested it averaged ~ 950w. Ambient temps are pretty mild to cool. Never tested it in hotter weather. Mostly because I'm rarely in hot weather.

I've though about setting it up on a timer to shut it down for a while at night. That is about all I've done is thought about it. The only time I've run low on battery power is when someone left the door open all day last summer.

One thing we discovered out shopping is that size of refrigerator does not necessarily determine power consumption. Some of the smaller ones used more energy than the bigger ones. Quality of construction has a lot to do with it.

I think those energy guides have take opening the door a lot. We don't get in the fridge much.

Photowhit · January 2012

Re: Tiny House Solar Config

icarus wrote: »

Remember we are talking out 100# not 20# tanks.

I was responding to multiple posts, I could have quoted "...Here a refill on a "20 pound" propane cylinder is reaching for $30.00..." By the Wayne

I always like a chance to explain how big a ripoff the exchanges are, here you can get an exchange for @$20 for 15lbs or go 2 blocks and have a full 20lb refill for $14...ouch! and some places charge much more.

icarus · January 2012

Re: Tiny House Solar Config

So,, I think you at right, 91,600 seems to b the right number. I am not sure where I got the 79k figure, but clearly it is wrong. Thanks for the correction.

Just as a further FYI. We go through a 60# tank every 6 weeks in the winter,, maybe 8-10 in the summer. That is for foreign, cook stove, demand hot water. ( water heat load is nearly zero in t he summer.)

Tony

stephendv · January 2012

Re: Tiny House Solar Config

We've just moved in to our small, but not tiny home, 516 sq ft and are loving it. Strangely it's more spacious than it first seemed without the furniture. The fridge hasn't arrived yet, but the one I ordered is the most energy efficient I could find - over here they're rated A+++ and this one consumes 157kWh/year =~ 430Wh/day. It's a combination fridge freezer with gross volume of 12.2 cubic ft and net volume 11.9 cubic ft.

http://www.clickelectrodomesticos.com/frigorifico-combi-mediterraneo-balay-3ksp6865.html Balay is a local brand so don't expect it to be available in the US, but Bosch and Siemens also have A+++ rated fridges available like this one: http://www.appliancesonline.co.uk/product/KG36EAW40-Siemens-Fridge-Freezer-White-24282.aspx

Volvo Farmer · January 2012

Re: Tiny House Solar Config

That's AMAZING efficiency! Seems like the rest of the world is well ahead of America in marketing energy efficient appliances. If I could get my hands on one of those, I'd shut down the propane Danby in a heartbeat Thanks for posting. I just learned something!

stephendv · January 2012

Re: Tiny House Solar Config

Volvo Farmer wrote: »

That's AMAZING efficiency! Seems like the rest of the world is well ahead of America in marketing energy efficient appliances.

When gasoline costs $6.7 per gallon, there're lots of motivation to build efficient appliances

techntrek · January 2012

Re: Tiny House Solar Config

stephendv wrote: »

We've just moved in to our small, but not tiny home, 516 sq ft and are loving it. Strangely it's more spacious than it first seemed without the furniture.

My wife and I experienced the same thing when we moved into our house. We toured it twice before buying, both times it still had furniture in it and the family room felt huge. Did the final walk through after everything had been moved out, and suddenly the family room felt much smaller. Moved our furniture in and suddenly it felt big again. Odd illusion!

Windsun · January 2012

Re: Tiny House Solar Config

stephendv wrote: »

We've just moved in to our small, but not tiny home, 516 sq ft and are loving it. Strangely it's more spacious than it first seemed without the furniture. The fridge hasn't arrived yet, but the one I ordered is the most energy efficient I could find - over here they're rated A+++ and this one consumes 157kWh/year =~ 430Wh/day. It's a combination fridge freezer with gross volume of 12.2 cubic ft and net volume 11.9 cubic ft.

http://www.clickelectrodomesticos.com/frigorifico-combi-mediterraneo-balay-3ksp6865.html Balay is a local brand so don't expect it to be available in the US, but Bosch and Siemens also have A+++ rated fridges available like this one: http://www.appliancesonline.co.uk/product/KG36EAW40-Siemens-Fridge-Freezer-White-24282.aspx

Just for comparison, I have an almost new Maytag (made by Whirlpool) that uses around $3 a month @ 11.4 cents/kwh, around 900 wh/day. That is actual usage with a power meter on it now for 43 days, not from mfg spec.

niel · January 2012

Re: Tiny House Solar Config

that 'frige is almost identical to my older 1997 roper (whirlpool) in looks and dimensions. mine draws about 1500wh/day so they improved it by 600wh/day. not bad. how's the pf on it as mine is about .59 if i remember right? i only ask as it is being backed up on my inverter.

niel · January 2012

Re: Tiny House Solar Config

hey coot,
what's bad britishism?

Cariboocoot · January 2012

Re: Tiny House Solar Config

niel wrote: »

hey coot,
what's bad britishism?

Let's just say you made a slight typo which becomes not nice if you're from a particular culture. Probably no one else would notice it, but ... you should hear my accent!

niel · January 2012

Re: Tiny House Solar Config

pm me on the details.

waynefromnscanada · January 2012

Re: Tiny House Solar Config

Cariboocoot wrote: »

Let's just say you made a slight typo which becomes not nice if you're from a particular culture. Probably no one else would notice it, but ... you should hear my accent!

Now you've got us all curious~ Hahahaha

Tiny House Solar Config

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