passive solar apartment with solar hot water

Did you keep the utility bills from the old place? Interesting to compare them month to month to this year's energy useage.

I noticed a huge savings when I insulated the attic and put in a programmable thermostat.

 

Congratulations on landing, Galaxee. That sounds like a very efficient house. Now you just need some PV panels to run the AC in the summer time...

You'll probably save so much on heating costs, the cost for cooling won't be so bad.

 

it's great to see this sorta thing pop up in an apartment setting and in NC no less! You'd think this sorta thing would get popular as a way to lure in renters. I hope it works out for you. I'm curious to see how it works out in the summer. It's so bloody humid in the SE. It never seems to cool off in the summer, at least on the coast. You're inland a bit so perhaps it's different.

 

<div class='quotetop'>QUOTE(Godiva @ Mar 12 2007, 02:54 AM) [snapback]404077[/snapback]</div>

I wish I could say this. We had only an inch to two inches of insulation in our attic and about a month ago, we installed another 12 inches. We were told our heating costs would decrease by about 40%. No such luck. For a single story ranch house with no basement, we pay over $200/month. I've sealed most cracks, have place insulation foam under our front door, got a new sliding glass door in the kitchen and put that plastic over our windows and it hasn't helped much. Now, I'm thinking maybe our ductwork has holes so we're now going to call an HVAC contractor to come have a look. I'm trying to do the right thing and it's not working and I'm more than pissed off.


<div class='quotetop'>QUOTE(galaxee @ Mar 12 2007, 02:45 AM) [snapback]404071[/snapback]</div>

Sounds neat. I thought that in passive solar design, they have awnings over the windows that let full sun in during the winter but block the sun from entering at all during the summer.

Thanks for posting these comments. When we build our next house, we're constructing it w/ passive solar in mind and would appreciate hearing how your energy use is affected.

I wonder it your feeties will be cold walking on the brick at night if you happen to get out of bed for some reason.

 

It is hard to retrofit an existing place that was built when energy savings was not a consideration. We have about 3200 sq. ft. with the great room, kitchen, breakfast area, and entryway sporting 20 ft. ceilings. Add to that wall to wall windows floor to ceiling and you would expect very high energy bills. This house is 5 years old and I contracted it myself. It has 6 inch walls (R21) and celings are R30. But the roof decking also has a radiant barrier with the attic containing continuous ridge venting along with continuous perforated soffits. The windows are 5/8 inch insulated glass with Low E coating plus thermally broken frames. But the big savings comes when you take into the consideration it is a GEOTHERMAL HVAC system. That system also captures excess heat for hot water anytime the compressor sections are running and the heat is not dissipated in the house. I can elaborate on this anytime anyone is interested.
Bottom line. The house is 60 miles north of Dallas. Our bills before the electric fuel surcharges averaged $175.00 per month. Now they are averaging $218.00 (reflects the 25% fuel surcharge increase over the last 2 years). You can add a radiant barrrier, increased attic ventilation, energy efficient HVAC to any home but anything more is hard to do to existing. The projected payback for the additional monies spent was 5+ years but paid back over a year early due to utility increases. Anyone considering new construction should give consideration to a super insulated, adaquatly ventilated, geothermal home. Good luck in the new place!

A note on programmable thermostats...your home has a thermal mass. Allowing that mass to cool off or heat up requires more energy to raise or lower that thermal mass than does just maintaining the temperature all the time. Unless you are going to be gone for more than 5 days, you should "set it, and forget it". It is like the ICE in the prius. It takes more energy to bring the ICE up to temp than to maintain it with block heaters and grill blockers. Hope this helps.

 

<div class='quotetop'>QUOTE(galaxee @ Mar 12 2007, 02:45 AM) [snapback]404071[/snapback]</div>

I have a neighbor near my hobby farm who built a house sort of like the one you're renting now. It's on a slab, no basement, and has radiant in-floor heat. The living room has the giant windows that face SE and S, with good roof overhang to keep summer sun off the jambliners

The floor in the living room is *black* tile, which at first really turned me off. However, when all that free solar energy is pouring into the house in January at -40, the floor quickly heats up to the point of being *much* too hot even to walk on with stockings, you need to wear slippers. At night, the floor gives off that heat, which takes a huge bite out of their utility bills.

The only knock I have against super-sealed homes is the lack of fresh air. You require mechanically assisted ventilation, which is an HRV (Heat Recovery Ventilator) up here, or probably an ERV or "energy wheel" in your climate.

<div class='quotetop'>QUOTE(galaxee @ Mar 12 2007, 02:45 AM) [snapback]404071[/snapback]</div>

Well, maybe the wall unit will be enough to take care of the humidity. I installed central A/C at my hobby farm to take care of summer humidity, not to worry about heat itself. It's a Bryant Evolution and I programmed it for priority dehumidification.

The compressor is two-speed, with a TXV (Thermal Expansion Valve) at the evaporator. So you can get superheat at very low airspeeds, which maximizes moisture condensation on the evaporator coil.

<div class='quotetop'>QUOTE(txav8r @ Mar 12 2007, 02:50 PM) [snapback]404285[/snapback]</div>

I now wish I had gone with a good quality geothermal heat pump. One of my neighbors near my hobby farm has one and swears by it. When I built the new home at my hobby farm 4 years ago, Manitoba Hydro hadn't offered the incentives and rebates. Now Manitoba Hydro offers very strong incentives and rebates, and it really makes sense to go geothermal.

"Free" hot water. Yes, in summer when you're using the loop to cool, you can use an optional desuperheater with a water-to-water plate heat exchanger to heat domestic hot water. Usually, you can leave the water tank breaker switched off all summer long.

About the only catch up here is that a lot of shady installers got cheap and put the ground loop only 3-4 ft down. At -40, the frost level can reach 5-6 ft down. The system is far more efficient if you go +10 ft down.

 

<div class='quotetop'>QUOTE(SSimon @ Mar 12 2007, 09:38 AM) [snapback]404243[/snapback]</div>

The 2" of insulation gave you probably 90% of the savings you will ever get from insulation. Piling up more over that gives you more, true, but its the first inch that really makes the difference, and the additional gain is a percentage of the heat loss that's LEFT. So if an inch cut your energy bill by 70%, the additional 12" might cut the additional heat loss (that 30% left over) by 40% (or 12% of the original total). There's a thread with the math on it here somewhere.

Having the HVAC guy check the ducts is a good thing to do; he can also check the furnace and make sure its working optimally.

 

<div class='quotetop'>QUOTE(fshagan @ Mar 14 2007, 12:29 AM) [snapback]405174[/snapback]</div>

Thanks for the explanation. That's probably why when I inquired about adding even a couple more inches, he said it wouldn't be economical. My furnace???, well it's brand new. I had it installed in a effort to reduce my energy consumption. I guess that's why I'm getting so aggravated. I've done everything possible to reduce our use and it's next to impossible. The only thing left to do is to caulk around my windows and I'm guessing this should help a bit. I put plastic around the windows but only affixed to the window pane. I wouldn't want to be performing all that paint touch up when removing the film. Leaking ducts are the only thing that could account for our high energy use. There was a flood in the crawl years ago and maybe they've rusted. Any other suggestions anyone has are appreciated. But, the way things are going, I think I'm doomed. My sister has a tri level with a heated basement and pays half what we do! Other than the windows and insulating behind my electrical outlets, I've taken every necessary precaution that I've read for energy savings. This extends to even installing landscaping to promote energy efficiency.

 

<div class='quotetop'>QUOTE(SSimon @ Mar 14 2007, 11:07 AM) [snapback]405439[/snapback]</div>

How old is your house? How old's your sister's? If the R values on your walls are low that could get you. I assume you've weather-stipped the doors and the like. Are there any pipes coming in from outside that have gaps around them? How many therms are you going through a month? Perhaps there's a lot of crud in the ducts that's stealing some of your furnace's output.

 

70's = my house; 70's = my sister's house. Yes, huge, one inch gaps around the piping coming into the house that I sealed w/ expanding foam. No, weather stripping of windows and doors are my next project. Therms used is over 200, up to 270, monthly in winter. That's a lot for a one story, small house, right?

 

That sounds high for therms. Our house is a 1978 tri-level, ~1300 sqft. I'll take a look at our records and see how many therms we used in JAN, which was a cold month here.

 

very cool (pardon the pun) indeed. What can you tell us about the solar water heating? To the best of your knowledge what percentage of you hot water needs is it providing?

 

thanks for the update. The solar water heating is still helping because it's keeping the water in the tank hot during the day. But yeah, if you're mostly draining the tank at night I wonder. There was a guy who posted about his solar setup several months ago (he's in FL). He had electric water heating as a backup, but he had disconnected it. He said that they hadn't needed it (the backup). So it could be that it really doesn't matter. Maybe keydiver will chime in about his experience. He's also in FL and has had solar water heating for a while. Bob Allen, in WA might have something to say about it as well.

 

Sweet. Glad to hear that it's working well for you. Now, if you didn't have any humidity that 76F would be even nicer!