passive solar apartment with solar hot water

[galaxee]

i've gotten a few inquiries on our new living situation, and now that we're finally somewhat (and i mean somewhat!) situated here i thought i'd post a few thoughts. i didn't think to grab the camera when it was, say, light out to take pics of the basic operating ideas of the house but i can post some photos later.

i was a bit skeptical at first, i'll admit, but if it works as well all year as it has the past few days i'll be quite pleased.

the house itself is a very tightly sealed place. it's got solar windows (whatever that means, i can't quite see what's so damn special about em) all facing south and brick floors. the window shades are referred to as "blankets" and are very thick with a reflective coating on the side that faces outside. on the roof is a solar collector for the hot water.

there is no central heat or air. this still makes me nervous as we don't do heat very well and this is north carolina. the heating/AC unit is similar to what you'd find in a hotel room and supposedly is sufficient to do the whole house. we'll see about that.

basically, the premise is that during the day, the sun comes in and heats up the brick flooring. the heat is stored in the brick until night, when you close the window blankets and the bricks keep the house warm. now there is no brick in the bedrooms because they're carpeted, so we found out we had to use the circulating fan to send warm air from the living room/kitchen area (main source of bricks) over to where we sleep. the first night we did not think of this. we were COLD. now, it's almost too warm in here. we have yet to use the little heating unit.

in the summer then, you open the windows at night and let cooler air inside and cool down the bricks to prepare for the upcoming day. and you don't open the window shades all the way during the day. this is where i get nervous because it doesn't always get cool enough at night for us. then again, we'll have some nice shade when the trees get some leaves back so maybe it's all planned out just right. i don't know yet.

the solar collectors for the hot water are supplemented with electric hot water in case we use too much. i haven't been able to tell much difference from a conventional system, other than seeing how tiny the water heater is. we haven't run out of hot water yet, though after a long long shower today i did feel it start to cool off and just cranked it up for more heat.

our only complaint? storage space! this place is smaller but i suppose for the price difference you come to expect that. we'll save a bundle in rent alone.

anyway, just some initial thoughts, i thought i'd put it out there.

[Godiva]

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.

[Bill Merchant]

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.

[tripp]

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.

[SSimon]

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

I noticed a huge savings when I insulated the attic and put in a programmable thermostat.
[/b]

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>

i've gotten a few inquiries on our new living situation, and now that we're finally somewhat (and i mean somewhat!) situated here i thought i'd post a few thoughts..........
[/b]

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.

[galaxee]

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

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.
[/b]

actually, our power company does have a "this year" and "last year" column on their bills for energy use. i will start to keep track of what we're saving. good thought... hadn't occurred to me. i feel brain dead after the past week...


<div class='quotetop'>QUOTE(Bill Merchant @ Mar 12 2007, 03:07 AM) [snapback]404083[/snapback]</div>

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.
[/b]

oh that would be so cool, but i doubt they're going to put any of those in. i certainly hope you're right about cooling costs. that's my only concern at this point.


<div class='quotetop'>QUOTE(tripp @ Mar 12 2007, 01:00 PM) [snapback]404228[/snapback]</div>

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.
[/b]

these are some unusual apartments, i'll give ya that. they're not brand new by any means, and probably older than both myself and DH (though that's not saying much since we're both under 30 ourselves)

the folks we rent from are former solar builder/contractors and apparently brought the whole concept of solar to the area. they are retired now and rent out apartments in a number of 4-plex buildings they built while they were active in their field.

it never does cool off much here but i'm hoping there's a nice cool breeze or something similar in this area. we're far from the stagnant marsh area where we used to live, now that was bad.

<div class='quotetop'>QUOTE(SSimon @ Mar 12 2007, 01:38 PM) [snapback]404243[/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.
[/b]

we do have awnings, actually, i didn't think of that. maybe they do help in the summertime.

i will update here and there about energy use. keep in mind we also use CFLs and all the appliances we've bought to date are energy star rated and such.

i do like the brick floors but we got a cheapie carpet remnant from lowe's for the living room floor and put an old carpet runner in the hallway. and i have nice slippers that DH got me a couple years ago. so far so good.

tonight when i get home i will post some pictures.

[txav8r]

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.

[jayman]

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

the house itself is a very tightly sealed place. it's got solar windows (whatever that means, i can't quite see what's so damn special about em) all facing south and brick floors. the window shades are referred to as "blankets" and are very thick with a reflective coating on the side that faces outside. [/b]

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>

there is no central heat or air. this still makes me nervous as we don't do heat very well and this is north carolina. the heating/AC unit is similar to what you'd find in a hotel room and supposedly is sufficient to do the whole house. we'll see about that.[/b]

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>

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. [/b]

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.

[fshagan]

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

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.

[SSimon]

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

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.