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7 Answers

Heat pump COP and preheating

Has anyone ever seen an analysis that indicates the benefit of having an air source heatpump run more before the nightly temperature drop in order to obtain a higher COP than later in the night?

A similar pre-charge could be done for cooling before the outside temp rose a lot.

In the past with leaky poorly insulated houses I don't think this made much sense, but now with some very tight and well insulated houses I belive it would be beneficial.

The main trick is to mine weather report data and control the thermostat based on COP curve, energy loss rate, and heat schedule.

In Energy efficiency and durability | Asked By Ed Miska | Mar 5 14
1 Answer

Opinions on the VENTS-US single room ductless ERV?

VENTS-US single room ductless ERV units

Any familiarity or opinion about the VENTS-US single room ERV called TwinFresh Comfo. Are the performance claims any good? For apartments, lofts, cottages and small homes? Can they be used in same building where exhaust-only ventilation is in the bath and kitchen?


Apparently Home Depot is where they sell:


In General questions | Asked By fitch plate | Mar 6 14
1 Answer

Can a furnace be cleaned and reused after a house fire? Or should it be replaced?

I am working with a homeowner on the design of an addition to a house. Prior to starting construction on the addition, the existing house had a fire which was contained to the laundry room. Smoke damage, however, is throughout the existing house. The mechanical room is accessed through the laundry room. The furnace was running when the fire started, and then turned off. There is evidence of smoke in the furnace (in the filter and at the connection to the AC). I have one contractor suggesting that the furnace can be cleaned, serviced and remain.

In Mechanicals | Asked By Corri Sandwick | Mar 6 14
1 Answer

Concerning moisture inside open cavity stick-built walls

My project is in DE near the beach - a high moisture area. I have a slab on grade "cottage". The walls are 2x4's on 2'0 centers vertically with 2x4's also on 2'0 centers horizontally to the outside of the vertical studs - covered by painted T111. The "lid" is conventional trusses, vented, with foil faced rigid foam on the underside of the bottom truss chord. It was supposed to be a garage but it has morphed into a secondary living space for overflow guests, parties, etc and I want to use an air conditioner in there.

In General questions | Asked By Greg Burnshaw | Mar 6 14
2 Answers

Water Heater selection help - Gas or Electric, Tank, Hybrid, Tankless?

I am in the process of needing to update my hot water tank (Currently a 40 Gallon gas water heater). I live in Michigan and have been trying to figure out what makes the most sense (Environmentally and economically). I am considering adding solar panels to my roof next year, so I was thinking of changing to electric but I have not found much information about electric tankless systems being used in Michigan other than I would need a large unit to provide for the entire house. I have 3 full sized bathrooms, a dishwasher a kitchen sink, laundry room sink and a wet bar sink.

In Mechanicals | Asked By Roger Ratkowski | Mar 6 14
1 Answer

Insulation / moisture

Hello, I am buying a concrete block house. I will have to do some extensive renovations. I have brought a structural eng. to the site . He has told me that the exterior concrete block walls and foundation are fine, as well as the attic system. The rehab needs to be done inside. Due to previous water leaks inside the interior footings,girt beams and floor joists have to go and be completely redone.

In Energy efficiency and durability | Asked By john afanasiw | Mar 6 14
2 Answers

Anybody tried out EXTOSEAL FINOC, an new watertight tape from Proclima and 475?

Just looking for experiences with this tape and what you found it capable of or good for. At $98/roll, experimenting with new products is expensive!

In Green products and materials | Asked By Keith H | Mar 6 14
5 Answers

Finished cathedral ceiling insulation options

Our den is extremely cold and have discovered that the roof has no insulation. Very thin bat insulation exists on the ceiling itself. This we found out when handyman took a look through one of the high hats.

Considering blown cellulose insulation so we don't destroy the Sheetrock, but I am concerned that its particles will come out thru the high hats and ceiling fan and will breath them. No estimate.

In Energy efficiency and durability | Asked By Martha Wong | Mar 5 14
2 Answers

Above-ground poured concrete interior insulation?

Hello all

We are planning to finish a portion of our basement. A few of the walls in the planned finished portion will be against the poured cement basement walls. The basement walls are 99+% above grade/ground. The house is a few years old located in the 4A region, close to the 5A region border in PA.

Currently there is insulation on the basement walls. It is fiberglass that is secured with a white wrap which is nailed directly into the cement walls. The white wrap appears to have a diamond pattern on it with tiny little pin holes. Pictures included.

In General questions | Asked By Justin E | Mar 5 14
8 Answers

Safest insulation material?

I would like to know what the safest material is for an attic. We have a converted flat roof - originally it was a flat roof and then a pitched roof was added on - so we have some space as an "attic" that we use for storage and the HVAC system. There aren't any rafters and our ceiling is wood planks (tongue and groove?). My husband put poly iso foam insulation but now I'm wondering if it's safe. I have a small child and I'm worried about the air quality, etc. and worried about the fire retardant in it...

Thank you so much in advance!

In Energy efficiency and durability | Asked By Yumi Kato | Mar 3 14
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