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11 Answers

So, I’ve been researching the proverbial pee-pee out of this question: dedicated ductwork for my HRV or simplified installation? Here are the pertinents:
• Climate Zone 6
• 2700 sq. ft. story-and-a-half house, along with a 2000 sq. ft. unfinished basement
• 4 Bdrm, 3 ½ bath house
• Double stud walls, spray foamed exterior sheathing and cathedral ceiling, very “tight” and efficient house planned.
• Geothermal ground source heat pump, with gas furnace back-up (Xcel Energy “dual fuel” program allowing electricity to be purchased at 40% rate for geo.)

Asked By Kent Jeffery | Apr 15 14
10 Answers

I have a humidistat sitting in my house the last few years, and have taken notice of the RH%.

I am concerned that an HRV will dry out my house too much. Location is Toronto which has cold winters (down to -18 celcius) and summers up to 30 and 35 celcius humid

With a forced air system with a humidifier installed, we go down to about 16% humidity in the winter on the coldest days. typical is around 20%-24% . In the summer we are at about 50-54% ish.

with these numbers would an HRV make it too dry, or would the numbers typically be affected only slightly?

Asked By cory b | Apr 13 14
1 Answer

Has anyone seen a review of this new HRV?

Although it is rather expensive, installation is dead easy and mechanically it is exactly what I've been waiting for for 35 years.

Consider this... when the occupants are active in the main living area, exterior doors probably get opened and closed a few times every evening bringing in significant fresh air. (This is an impossible calculation, but could be verified through measurement)

Asked By Kevin Dickson, MSME | Apr 11 14
4 Answers

Just put a Mitsubishi MUZ-GE24NA in my home. I checked the standby loss with the inside unit turned off and found that it was drawing 170 watts. I called Mitsubishi and they said it is the compressor heater and it is always on any time it is below 66 degrees.

Needless to say I'm very unhappy to have put in something in that will use around $15 dollars a month before it even produces heat.

Has anybody else had issues like this or do I have a defective unit?

Asked By Paul Lennon | Apr 8 14
1 Answer

Has anyone tried to quantify heat loss through the outdoor parts
of typical heat pump lineset installations? Does it matter much?
It occurs to me that some token amount of insulation is applied
there, but is it sufficient? Especially on the vapor line, which
runs pretty warm in heating mode and the farther the lineset goes
before coming indoors, the more it's exposed to a high delta.

Trying to ballpark it, assuming typical pipe insulation with about
a 1.5" outside diameter and half an inch thick, what is that stuff
usually, about R-3? Assume a ten-foot length running outdoors to

Asked By Hobbit _ | Apr 2 14
1 Answer

Let me thank you in advance for your advice.
We're putting a minisplit ductless system into 3 rooms. 1 compressor and 3 heads.
I've gone to 3 contractors and each has given me different information. 2 of the contractors use Mitsubishi and the third uses Fujitsu. Needless to say they all include heat pumps.

The house is a 1929 stucco structure

1st room is a bedroom on second floor
14'3"x 10'6" x 8' ceiling
exterior wall on one side and one end
18"x 2'9"

Office on third floor (no attic steep pitched roof)
9'9" x 10'8" x 8'10" ceiling

Asked By jon keller | Mar 31 14
4 Answers

Climate zone 6.
Approximately 1000 square foot area. Will be very well insulated. R40 floor, R60 or better roof, R30 walls with well detailed air sealing. Approx 76 sf of triple glazed windows.

The floor plan is very open, so I'm hoping one unit will be sufficient, with some electric baseboard supplemental heat in strategic areas.

This winter was horribly cold, with many days below zero, but I wouldn't call that the norm. The coldest day was approx -18 below for the low, and approx -8 below for the high.

Asked By Rick Van Handel | Mar 26 14
9 Answers

I am on the energy committee in my town. (It's a volunteer committee that reports to the town government, promoting energy goodness to the municipality and residents.) Our committee recently was contacted by a resident in a rental home with a question about a mysterious spike in electric use.

Asked By Jonathan Teller-Elsberg | Mar 26 14
2 Answers

Energy modeling confusion. How do I find an independent energy rater that is familiar with up-to-date heating and cooling systems for a PGH?

We are designing our own home and have read the blogs supporting and discouraging the use of energy modeling. How do we find someone to do an energy analysis who is not selling a specific HVAC product but can recommend an HVAC system that's appropriate for a PGH?

Asked By russell berenson | Mar 26 14
4 Answers

I have an ongoing renovation of my own house but any info will certainly apply to other projects that fall into this same scenario or possibly another job that I or others may encounter.

The current conditions are:
1. Hydronic radiant heat installed under existing 3/4" board sheathing which is under two layers of wood flooring for half of the area, the second half is tile underway, same build-up thickness.
2. 5 loops cover 925 s.f of first floor area, fairly equally sized loops.

Asked By Robert van Wert | Mar 24 14
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