Community: Mechanicals

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3 Answers

I've heard that some heat recovery ventilators produce ozone. Is that true, and if so how?

How can you know you are buying one that doesn't?

Asked By mark romwalter | Oct 8 17
3 Answers

HVAC setup in small basement

Hey folks,

Asked By Jamie Royal | Oct 5 17
4 Answers

Fresh air for mini-splits

My HVAC contractor is planning to use Mitsubishi mini-splits, some ducted, some not. I am on board with this idea, but we are looking at fresh air alternatives. I was originally looking at the AirCycle g2, but it seems that the Mitsubishi wiring may be a problem, since it is not "standard". Also, it seems the Mitsubishi fan runs continuously, albeit at a low level. Other than an ERV, which may be a more costly alternative in my climate zone, what are my alternatives for getting fresh air into the home?

Asked By Norman Bunn | Oct 3 17
53 Answers

Zone 6b, Mass. Coast, mini split / Fujitsu?? Mitsubishi?? size?

hello,
I live in a coastal town north of Boston. My 1200 square foot house (600 upstairs, and 600 downstairs) is heated via electric baseboard heating. I never go above 60 degrees in the winter and still spend over $400 per month and this is with each room with its own thermostat and me turning them all down to mid-50's when no one is around and only turning up those rooms where we are. It is ridiculously cold in my house in the winter.

Asked By indoorsy | Sep 5 17
2 Answers

Dettson furnace and air conditioner

Does anyone on this forum have experience with Dettson furnaces or air conditioners? They offer a line of furnaces, called Chinook, starting from 15K btu/hr. They also have central air conditioning compressors, called Alize, starting from 9K btu/hr. The Alize literature also quotes a heating range, so apparently they are actually heat pumps. The furnaces modulate from 40-100% of rated capacity and the air conditioning compressor modulates down to 25% of rated capacity.

Asked By Reid Baldwin | Sep 21 15
5 Answers

Bath fan to nowhere

I first have to say that I really appreciate this forum and all to contribute to it.

My question has to do with repairing a bath fan in the house we are living in. I opened up the fan in an attempt to find out why I wasn't getting any air flow through it. I found out that when it was originally installed no duct was ever attached. I can reach through the hole and grab the insulation! The insulation was packed right up against the flapper valve, keeping it from opening. The good news I guess is that not a lot of hot humid air wasn't being dumped into my attic space.

Asked By Kevin Camfield | Sep 27 17
3 Answers

Ductless minisplit vs. air-to-water heat pump

Hello everybody, I am in the very beginning stages of my house design and I keep bouncing between using mini splits vs Air-water heat pumps and fan coils and possibly a radiant slab.

I intend to insulate my house very well, basically ICF construction with rigid foam above the roof sheathing and cellulose loose fill making up the rest of my roof insulation. Trying for somewhere around R-60.

Asked By youngb556 | Sep 26 17
2 Answers

Exhaust-ducted HRV vs. simplified

Hello! I'm looking to put in an ERV, after I realized I could probably DIY for not much more than CFIS. I am stuck planning the ducts and wondered if you could lend me some insight.

I have an open floorplan 2500sqft place. 2 stories plus basement. Fairly tight envelope, and we continue to seal here and there. I expect to be around 700cfm50 soon.

I think running supply ducts is basically out for me, but I think that's OK because my return air grills are in all the right places already, so as long as I can seal up my HVAC ductwork, I hope that will work well.

Asked By Pshyvers | Sep 26 17
2 Answers

Is an HRV/ERV absolutely necessary?

Hello GBA readers

I have recently finished some energy upgrades to my 1983 house in climate zone 6 (southern ontario). Work included exterior rigid and attic insulation, air sealing, new triple pane windows and patio doors and the installation of a couple fujitsu ductless heat pumps. My energy advisor recently completed a follow up blower door test and results came in at 1.9 ACH. Not bad, but certainly not super tight.

Asked By Jeremy Archer | Sep 26 17
6 Answers

ICF home and ventilation

We built our 2300 sq ft home last year and moved in January of this year. We have a heat pump air conditioner and I have the fan set with my Nest thermostat to go on every hour. We also have a dehumidifier going. Despite this our humidity level in the house is 45-50%. We don't see condensation in any of the windows. We are worried about the possibility of mold and poor indoor air quality. What are your recommendations?

Asked By melsie | Sep 24 17
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