new home

Brock · February 2008

So we are building a new home and the thread on building made me think I might as well post what we are doing.

The home is about 2100sq ft on the main floor with a walk out basement on the south side, north side has very few windows and the basement is completely underground on the north. We have a 4 ton geothermal field with a 3.5 ton unit. I am not really familiar with geothermal, yet. Our intention is to heat our indoor pool (20,000 gallons) (nice heat sink) with the geothermal. We also have pex under the basement slab and under the main floor in all the tiled areas as well, about 1/2 of the main floor. I intend to use pool water circulated through the pex to supplement heating. We also have a natural gas forced air furnace. For cooling in summer we will use the heat pump (with manually switching from the field to the furnace) to cool the forced air for the house and heat the pool. The geothermal also has a "super de-heater" connected to a 40 gallon pre water heater. Also any water entering the pre tank is run through a GFX hot water heat recovery unit. It lets drain water heat the incoming water before it hits the pre tank which is heated by the geothermal, then passes to a natural gas 50 gallon regular heater (hopefully won't run much).

I will also have our small solar PV (500w) right now, but added mounts to hold about 4 kw above the nice south facing garage roof.

We also have an air to air heat recovery unit on the pool exhaust. So we exhaust that air which heats up incoming fresh air to the home keeping the pool room at a negative pressure from the house.

All the basement cement exterior walls have 2 inch on the outside and 2 inch under the slab and between any connections to the exterior walls. The pool has an additional 2 inch of pink foam around the entire shell. The above ground walls are 2x6 with 2 inches of urethane foam and then batts to finish filling the space. The siding has an insulation core with a rating of about R2.2, not much bet something. All the windows are good double hung Andersons with full storms.

We will hopefully move-in in 6 to 8 weeks.

The only sub that doesn’t think we are crazy is our geothermal and he is excited about us trying all these weird things and wants us to keep him informed on how it all works. The plumbers and electricians are just confused, but are willing to wire and plumb things in ways they never have before.

Telco · February 2008

Re: new home

Wow, wish I had your money.

Sounds like a pretty nice setup you have there.

I've been in a few homes that had some sort of standing water such as your pool, and they've all had a watery, high humidity smell inside. Are you going to have a dehumidifier in the house to help control the water? Evaporation of the pool is going to be 24x7, and while I understand the house will have positive pressure, things still tend to circulate inside an enclosed space.

I've also heard that there are problems with geothermal heat pumps, with the lines breaking in the ground. This was from a fellow that installs geothermal and air to air pumps. Apparently the ground loops are warrantied for 50 years, PARTS only. Labor is not included in this, and it costs several thousand to reinstall a ground loop. And, there is a high failure rate of the ground loops within 5 years. What's worse, when the loop is installed they have to use a special heat transfer cement to install it that glues itself to the ground, so the old hole can't be used. They have to sink a new hole. The cost difference is that folks that have failed ground loops are able to go with a high SEER air to air heat pump. The guy I was speaking to doesn't live in my area and wasn't trying to drum business up, this was a side discussion on a performance vehicle board I hang out at. If you haven't installed the ground loop yet, might discuss this with your geothermal tech and refuse to have one installed unless labor is also covered. I was pretty hot for one of these, until I found out about this little unadvertised issue. Kinda ticked me off, really.

If you don't mind me asking, what did the poly spray cost? I've not been able to find a good guesstimate anywhere and don't want to bother any contractors with questions this far out from my own build.

mike95490 · February 2008

Re: new home

indoor pool ?

I see you have a air-air heat ex on it, but will that be enough to keep the humidity down ?
is this a swimming pool, or a heat sink pond - maybe float some 2" styrofoam cover over it to reduce evap loss.

Sounds interesting, keep us posted

Brock · February 2008

Re: new home

We are doing a lot of this ourselves to save money, all of the pex a lot of the “extra” insulation. But we did bit the bullet and paid almost an additional $17k for the geothermal, but we did eliminate about $4k in pool heaters and the like.

Our field is in and has a 10 year warrantee on parts and labor and then a 50 year prorated labor from 10-50 with parts out to 50. We spoke with two other customers of his; one about a 12 year old system and both had nothing but good things to say. He was the only installer who even understood what we were trying to do and understood it enough to be really interested in the work.

I can’t remember what the SEER was; I know it was about twice what the air to air unit was. Our problem is we spend too much time below 20F in winter and at that point it starts to approach resistance heat where the ground source was steady all year. Our field was buried at 10 feet, he like to go 6-10 and I encouraged him to go to 10 feet, cost a bit more but I think in the end it is a better idea. His only concern was that we wouldn’t ever be warming the field in summer, but he oversized the system should about a factor of two.

We had a pool in our last house and never had any issues with humidity, as a matter of fact we had to add a whole house humidifier because it was to dry. We are really good about keeping the pool covered when not in use which makes a HUGE difference. Yes we leave the exhaust running 24x7 although I did have it set at one time with a humidistat and that worked as well but we would get some pool smell in the house when it shut off so we went back to 24x7. When we built our first house everyone told us it would never work, we have had two different HVAC engineers come out and inspect it all and were amazed. I have no concerns about humidity after our last house. The pool is sealed from the rest of the house with vapor barrier and then durarock and finally dryvet, typically used on an exterior of a house.

The pool is roughly 15x15 at a sloping 1 to 4 feet, then a drop off in to 15x15 at 9 feet deep. There is also a 8x7 hot tub sort of inset/offset on the shallow end.

I don’t know the cost of the spray again we had it in our last house and it is amazing how much better it seals the exterior walls.

Telco · February 2008

Re: new home

Excellent, covered bases are best. If it lasts 10 years with no ground shifts, likely it'll go the full 50.

icarus · February 2008

Re: new home

Where are you?

It seems in a dry/cold climate the pool would be a great source of controlled humidity. In the muggy summer of the S.E US perhaps not.

Icarus

niel · February 2008

Re: new home

brock,
sounds like you're getting your dream home. sounds very nice. are you going to address the pvs later or before you move in. for that matter you may have moved in already so fill us in on the planned pv layout. i would imagine you'll be a bit closer to work so you don't have to run the pants off of your truck in those cold wisconsin winters. did you already sell your other house only out of curiousity?

Brock · February 2008

Re: new home

Green Bay, WI. We moved a lot closer to "town" about 1 mile from my work ( can see it actually) and our kids school (we can see that as well). I hear they even deliver pizza to your house? weird...

I suppose you could use the pool to add humidity, but I would rather use a regular simple whole house humidifier, easy to control and simple.

Niel yes our "old" house we also built is sold, we had an offer in less then 3 weeks, maybe we didn't ask enough, but it's done and sold. We are currently living with my parents, its cramped, but working. I have two #4’s from the attic of the garage (just below the panel mounts) to where the MX-60 will be in the basement. I also have an empty 3 inch PVC run down from the attic to that same area, just in case. Right now it is sealed on both ends.

I did put mounts on the garage roof, perfect clear shot due south. I think I have enough mounts for about 4kw. The main part of the house also has a nice south shot, but my wife wants me to avoid over the house if I can.

lamplight · February 2008

Re: new home

"if you can.." sounds like my wifes toleration level which i admit is very generous like yours sounds, congrats on the new house i thought the old hs was gorgeous from pics i saw, but you will absolutely love how pizza delivery enhances your life

Brock · February 2008

Re: new home

LOL, ya we had a great location before but the kids educations comes first. And being our second build we improved on a bunch of small things from our last house.

new home

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