I have a client who needs your help. In the early 80's, he and his wife built a beautiful off-grid home on a small island near Fort Myers, FL. It currently serves as a convenient getaway, but as they…Continue
"theoretically, let's say you perfectly isolate the HPWH from a heat source. The HPWH's will eventually cool the air to the point that mold will grow. Here's the math:
30x30x8 = 7200 ft3 x 0.075 lbs/ft3 = 540 lbs of air
540 lbs x 0.24…"
"Interesting idea. Commercial roof on a slope!
Typical density for roofing spray foam is 2.5 to 3.0 lbs/ft3, depending on expected foot traffic, with R-value of about 6.5 per inch.
On 'flat' roofs, the mix is normally set for a slower…"
"You might consider a commercial grade roof foam spray (higher density than normal CC Foam) with a coating over that - if they want metal over that, that's fine as there are some special clips & rails they can use but the clips need to be…"
I have a client who needs your help. In the early 80's, he and his wife built a beautiful off-grid home on a small island near Fort Myers, FL. It currently serves as a convenient getaway, but as they approach retirement, they want to install a limited amount of air conditioning in the form of a couple of small, high-SEER ductless mini-splits. The aging 12V PV system is quite small -- the refrigerator is propane powered, and there's no well (fresh water supplied by rainwater collection). So…See More
"Regarding Sanden... US distribution is fairly new so I imagine they make it easy to set up an account, or would sell direct. The plumber would have to be on board, though.
The current model is good to -15F, and the forthcoming Gen3 is good to -20F…"
"Yes, now that I've taken time to make sure I understand the physics, I'm in full agreement.
Consider that with an air-air heat pump or A/C, the heat rejected by the condenser is roughly the same as the heat absorbed by the evaporator. A…"
"Since others reactivated this thread, I'll chime in. In recent years I been including DHW distribution in my design review conferences. As others noted, each house is different, requiring its own solution.
The device Sean mentioned in the OP…"
"It' irrelevant whether the basement is intentionally heated now. My point is that if you install 3 HPWH's down there, it makes no sense to NOT intentionally heat it. The heat pumps must get their heat from somewhere. Without a heat source…"
"Hi Brad, as you know, a heat pump's capacity and COP depend largely on ambient temperature. But in situations like this where heat pump operation will have an out-sized impact on ambient, you essentially create a feedback loop.
"I'm with you on this one PJ (for once!). All else being equal (or equally bad), setback has the potential to save more than downsizing source equipment, although if the AC is grossly oversized, say, 200% or more, who knows. It's true that…"
"Ted, by saying that homes that benefit from setback are somehow broken, you're making a huge generalization, and one that flies in the face of physics and common sense. You wrote: I ask how much and they say "a lot". I can't…"
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