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16 Answers

Boiler upgrade recommendation?

I’m currently looking to upgrade my old boiler as it developed a small crack and is leaking. My current boiler is a P-468U-wt (151,000 btu/hr) Weil-McClain oil-fired boiler with a 40-gallon hot water holding tank.

I’m getting two different suggestions from two of my plumbers and would love some input on their recommendations. One recommends replacing it with an Energy Kinetics System 2000 and the other one is suggesting a Navien Combi-boiler.

Asked By Joe Pavia | Jul 1 15
6 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
2 Answers

ERV exhaust up a chimney

Can I run the main exhaust pipe of my ERV into the abandoned flue of my chimney?

Asked By Fred Richards | Jul 4 15
4 Answers

Open-air barn

We are designing an unconditioned "party barn" in Central Texas for occasional gatherings for groups of various sizes. The barn has about a 1,400 sf footprint -- 1,400 sf at the ground floor then there is a loft that is about 200 sf. We have Big Ass Fans for air movement but would like to add an attic fan to exhaust the warm air that will build up in the loft/attic space. How do we calculate the amount of CFM that the fan should be moving?

Asked By Heather Gayle Holdridge | Jun 26 15
2 Answers

California heating question

I have a 1910 craftsman home in the Bay Area where we might need cooling 4 or 5 days year and it typically does not get too cold. We are redoing the basement (seismic) and attic (new roof, beefed up framing) and will install a solar PV system. I will most likely go to a heat pump water heater and a new heating system (presently have floor furnaces). I am thinking about a mini split system or a ducted heat pump system with the ducts in the attic. What are the advantages and disadvantages to both? The house is 3 bedrooms and about 1800 square feet.

Asked By rob manheimer | Jun 29 15
1 Answer

OTR Microwave as range hood in tight house?

I'm looking at a range hood for ventilation in a new, tight, house build. I've read the articles like:

which talk about buying a range hood with a small exhaust fan. Martin recommends 150 CFM to 250 CFM with a tight house.

Asked By Nick Hall | Jun 26 15
29 Answers

Radiant floor heating using heat pump?

We live in a Zone 7 area and are building a one story 2000 sq ft on a slab and have decided we would like to heat the house with in-floor radiant. We have been told by HVAC specialists that the best solution would be geothermal, followed by hot water heat pump, electric hot water, then forced air heat pump and electric radiant. We don't have natural gas so that is not an option. Geothermal is out as it is nearly three times the price of the other solutions and this is a retirement home.

Asked By John Ball | Jun 19 15
4 Answers

Supply ventilation - energy use impact

I downloaded BEOpt and EnergyPlus and have been experimenting. Some of the outputs are surprising at first but make sense when I think more deeply, However, I have not been able to make sense of the results I am getting for different ventilation options. I am trying to determine if there is some physics advantage to supply ventilation or whether the results I am getting are modeling errors.

Asked By Reid Baldwin | Jun 22 15
11 Answers

Heat loss calculation and minisplit location questions

I am building a modular energy efficient house in N. Reading, MA. The modular company PBS has a lot of experience building energy efficient homes which is why I am surprised at their heat loss calculations. The house is 3860 sq ft not including the walkout unheated basement. PBS uses the ADA in their building method and the other house details are as follows:

House is oriented northwest-southeast
Paradigm Triple Glazed Windows U-.21 Innie
R-10 under slab
R-20 on front and side concrete basement wall, back and garage are the same as above grade

Asked By Arthur Ledoux | Jun 21 15
3 Answers

ERV / HRV Details

The more I read both here in discussion forums and in articles, the more I ponder various concepts, and the more perplexed I end up. I'm a homeowner undertaking a gut-renovation on nights/weekends/holidays. I'm trying my best to balance idealism and the realistic necessities of my budget.

~2000 sf house in Southern CT; CCSPF insulation throughout; Hydro-Air HVAC system. I'm pretty well convinced that an ERV is the correct choice.

Asked By Matthew Kreuzkamp | Jun 22 15
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