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HVAC contractors: Please take this fault prevalence survey!

Not a question, but a request for the community:

I sit on an ASHRAE committee that is developing standards for automatic fault detection and diagnostics (AFDD) for rooftop package units.
We’re trying to gather data on the prevalence of various fault types (to help determine the cost-effectiveness of the AFDD systems). The head of the committee has put together a survey aimed at field contractors, to try to gather more information.

The more input we get, the better, so we would appreciate any contractors who would take this brief survey:
http://www.surveymonkey.com/s/AFDD

Asked By Brent Eubanks | Jan 22 13

4 Answers

Should I expel my ventilation system air onto my hybrid heat-pump water heater? Should I vent the WH into my crawl space?

For a superinsulated house being extensively retrofitted in South Jersey (R-40 walls, R-70 attic, triple pane windows) with a permanently wet crawlspace (riverfront, high water table), I am considering positioning the exhaust duct from the Fantech heat recovery ventilation system to expel over the top of a hybrid heat pump hot water heater. The HWH will be in the insulated unheated 2 car garage, possibly next to a geothermal water-to-air heat pump. I would plan on turning that exhaust vent away from the HWH in summer.

Asked By Michael Arnold | Jan 22 13

1 Answer

Bathroom ventilation

This is a followup on a question by Jim Blodgett on 7/5/2009 titled Bathroom/Laundry Ventilation through HRV. If I understood the responses to that question, a HRV can exhaust a full bath without separate ventilation through the roof or wall. There was some reference to boosting the exhaust into the HRV with a fan while showering. This in addition to the boost to maximum of the entire HRV by a wall control.

Asked By tom ruben | Jan 21 13

4 Answers

Achieving net zero in a row home with one minisplit per floor?

I would like some opinions from all you smart people.

I have read many of the articles/posts on this site about a one head per floor minisplit approach for a net zero buildings. I do gut renovations of row homes in DC and have LEED Platinum certification on some, but have not achieved net zero. But I really want to!

Since these are existing ~100 year young brick rowhomes, mostly with attached frame porches, we cannot achieve a passive house tightness with our current construction techniques. We achieve in the neighborhood of 3.5 ACH50.

Asked By Tanya Topolewski | Jan 18 13

3 Answers

Is a 16 SEER air conditioning system worth it over a 14 SEER in Houston, TX?

Building a new house, 1.5 story and looking to get the most bang for my buck. Doing 2x6 walls with polyseal spray and cellulose insulation. Will a 16 Seer be worth the addition $3-4 k I have been quoted? Energy prices here are currently 10-12 cents per kw hour, but do rise occasionally. I am most concerned about home comfort though and have been told by some folks that higher seer units in this humidity are not worth it. Any thoughts?

The house is appx 3500 sq ft with 2700 down and 800 up. I am looking at two units, a 4 Tom down and a 2 ton up.

Asked By Dustin Gohmert | Jan 16 13

7 Answers

Passive HRV - pressure balance ..a few questions

I would need help or pointers to understand a few things about air in a tight home
and HRV/exhausts/ pressure balancing.

Situation is the following :

Planned to run a DIY central AC at first using some GEO + AC pump..i scrapped that
and will be installing mini splits for AC next year .
Heating is all handled by electrical underfloor heating ...

Still have the 4" PVC ducts going through the house that will be used with 4" fans
in the machine room to "mix" and redistribute air at a moderate level

Asked By Jin Kazama | Jan 13 13

5 Answers

Sizing an HRV

I am working on sizing an HRV for my son's house. Using ASRAE 62.2 I get 77cfm. Using ACHnatural of .35/hour I get 144 cfm. Using Venmar's tables I get 160/80 cfm for the high/ low. Using 10 cfm/room and 20cfm for master bedroom and basement I get 180 cfm. I wonder if some of the higher numbers from the manufacturers are trying to account for high speed venting of bathrooms. However I wonder even at 180 cfm with ten supply and return grilles if he HRV can pull enough air out of one bathroom to stay ahead of a long hot shower on a cold winter's night.

Asked By Steve Kent | Jan 13 13

2 Answers

ERV ducting - how to insulate?

We have an ERV, which works great for our house, which is in a cold climate (i.e. this week will be below zero at night for the next four days, and teens during the day). This is our second winter in the new house. We have discovered that due to location, a hot water line (PEX with R-4 insulation) crosses over the ERV incoming duct in the between-floor truss level. It has frozen at this point.

Asked By Richard and Miranda Menzies | Jan 12 13

1 Answer

HVAC Design - Central Jersey

I"m looking to hire someone who is knowledgeable about building science to work with me as a consultant on the design (and possibly installation) of an HVAC system for my home remodel in central New Jersey. Can you recommend someone? Thank you. Deidre

Asked By Deidre B | Jan 12 13

10 Answers

Installing a Condensing Modulating Boiler with an Indirect Hot Water Tank; still efficient w/ old plumbing and cast iron radiators?

Is installing a condensing modulating boiler w/ indirect hot water in an old home with cast iron radiators in Minneapolis still efficient if the house has old 2”+ dia. cast iron piping and cast iron radiators? I’ve read that if the water returning to the boiler isn’t under a certain temperature the heat exchanger won’t function efficiently. Also need to add an additional zone for a previously unconditioned space where we would like to use a wall hung radiant panel.

Asked By j chesnut | May 17 10

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