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0 Answers

How much energy does the evaporator coil waste?

While working through Manual D calculations I was surprised at how much of the total static pressure from a blower motor is dropped through the air conditioning evaporator coil. In my case I had a drop of .3 iwc at the coil for a total external static pressure of .7 iwc at 990 cfm. That's almost half of the blower load being used to push air through a coil that in my climate (zone 5) is just in the way most of the year.

Asked By Jonathan Dalton | Jul 28 15
6 Answers

Is a ductless minisplit appropriate for a house with primary wood heat?

I am contemplating installing a ductless mini-split heater in our new build house in Southeast Alaska. The climate is of course very wet, with fairly cool summers and fairly mild winters with the occasional cold snap.
We heat primarily with wood. Is a mini-split heater an appropriate choice when the wood stove is expected to do 80% of the work of heating? We want an auxiliary heater that will simply limit how cold the house will get while we are away for a long day or a weekend (to 50 degrees or so), but will not run at all when the wood stove is going.

Asked By Justin Smith | Jul 23 15
4 Answers

How much more efficiently does a ductless mini-split perform below peak demand?

My Manual J load calculation for my the 960 sf house I'm building in central Arizona shows a heating load of 13,535 BTU and a cooling load of 11,860 BTU.

I'm debating between two ductless mini-splits:
Panasonic E12NKUA with inverter: 12,000 BTU Cooling 13,800 BTU Heating, 20 SEER 10.6 HSPF
Panasonic E18NKUA with inverter: 17,100 BTU Cooling 20,400 BTU Heating, 18 SEER 8.5 HSPF

Asked By Jeff Cooper | Jul 27 15
17 Answers

How do I get and keep air out of my geothermal loop?

We have a "closed loop" geothermal heating and cooling system. 97 wells 300 ft. deep. 4 story building. 36 water source heat pumps. 72 electric water pumps. 219 ball valves.
There is no way at the high point (attic over 4 story) to release air and no easy way to add water to displace the air. The contractor keeps trying with their big pump and tank trailers to purge the system by driving the air bubbles out through the basement. No surprise to me, having observed the bubbles in my bathtub travelling upward, this approach keeps failing.

Asked By Todd Conradson | Jul 1 15
14 Answers

I need advice on the design of an energy-efficient heating system

Just completed re-framing a home in NH. Used Zip R on the outside, CC foam inside. I had planned on going with radiant heat but from the articles in GBA, this may be overkill. I have spoke with a few propane companies and 2 plumbing companies and have not seen anything that is right. Most do not seem to be up to date ( old school) Who out there can I contact to design the proper system without trying to sell me on their systems?

I am truly thinking of going with return hot water as this system has served us well in our last home for 25 years.

Asked By Joseph Maraldo | Jul 22 15
5 Answers

Managing humidity in a tightly constructed ventilated house

In a tightly built, newly constructed house in Zone 5, we're experiencing higher than desired humidity. As expected, the air conditioning does not run often enough to effectively dehumidify, even in the peak heat of an Illinois summer. I'd value your recommendations.

Here are some specifics:

Asked By Dave Brooks | Jul 23 15
6 Answers

Are Duct Booster Fans Crazy? Or will they solve insufficient cooling air reaching 2nd floor?

2nd floor of my Kansas City 24yo home (bought 3 years ago) is consistently 6-12 degrees (F) warmer in summer than first floor. The problem I noticed from Day 1 is simply that the 2nd floor does not get enough air from the HVAC system. With the house fan on full blast, you can barely feel any air coming up through the floor registers in the bedrooms, while the registers downstairs are blasting out cold air.

Asked By Stuart Miller | Jul 14 15
1 Answer

Kitchen vent fan cfm's

I went crazy with my kitchen vent fan and installed a huge commercial kitchen vent. I love having it there in combo with our six burner range so it was in fact a good idea. Problem is , it sucks every bit of air out of the house and I would be scared to hold a small baby or puppy under the thing in fear of it being launched out of the house. In the middle of summer you can feel the temperature rise in the house. It is probably about 6-700 cfm. Here is the problem: I only had room for a 6" line under the oven for a makeup air vent.

Asked By swgold goldstrohm | Jul 11 15
10 Answers

Do sumps pumps and drain tiles create a self fulfilling prophecy?

This may seem like an odd question so let me explain myself, and to be clear it is mostly philosophical and out of curiosity.

I own/have owned/lived in many different buildings in the Chicago area. My parents house is also nearby.

Asked By Michael D | Jul 6 15
13 Answers

Water-source heat pump sizing

My 2-ton Carrier water source heat pump needs replacing. It's a condo, so I own the heat pump & handler, but not the water loop. I think I'm going to replace with another Carrier, but I'm considering downsizing to a 1.5-ton unit.

Asked By David Hicks | Mar 19 15
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