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15 Answers

Is a single head minisplit practical?

This is a mostly accurate plan of dear, old Mom's house.
2265 ft²; zone 4 marine; target ACH50 = 1.5; 5000 HDD; 22°F design temp;
2x6 walls w/2 stud corners, 24" o.c., 1½" horizontal cross-hatched walls (similar to "Mooney"), 7" of dense pack cellulose; front wall faces north; awesome PV potential on south facing roof.

Asked By Mark Walker | Apr 27 17
1 Answer

Will pocket door gaps at jamb allow avoiding a transfer duct?

Hi there: I'm trying to calculate undercuts necessary for balancing an HVAC system in a couple new residences. But then it occurred to me, that since all the doors are pocket doors, and since the Johnson Hardware we're using specifies a 3/16" gap between the jambs and the door panel on either side of the door, that this gap could be considered a "transfer grille" of sorts... The smallest 30x80" door would therefore have the equivalent of 20in2, not including any undercut.

Am I thinking about this in the right way? Do these 3/16" gaps give me what I'm assuming they do, in terms of airflow?

Asked By jonathan nagar | Apr 25 17
2 Answers

Hydronic tubing above or below subfloor?

I'm getting ready to do renovate my 1956 cape cod in Delaware. The house is heated with hot-water baseboard radiators throughout (supplied by a 120,000 BTU gas-fired boiler at 180F). In the remodeled kitchen, I'll be putting cabinets where the existing radiators are. Floor will be ceramic tile rather than the current vinyl sheet, over 3/4" plywood.

While I could install toe-kick radiators under the cabinets, I'd prefer in-floor hydronic heating throughout the kitchen. I've had it in a couple of prior houses, and liked it a lot.

Asked By Tim in Delaware | Apr 24 17
18 Answers

Warmboard with Ductless System?

Newbie here, so pardon my ignorance.

We are about to start designing a home in the DFW area (Zone 3).
Home will be a 2-story open concept with about 5,000 to 5,500 SF, properly insulated for the area. Despite the size, plans are to go with about 20 KW of grid-tied Solar Panels with a Powerstation 247 system.

Wife wants "Warmboard" as the heating source for at least some of the areas. I would like to have a VRF Ductless System for cooling and heating. Is there anyway to marry the two so that we stay "married" ? :-)

Asked By Rodgo | Apr 19 17
9 Answers

Gas heated steam radiator system


Asked By Daniel Herskowitz | Dec 5 13
24 Answers

Slim duct mini-split concerns

Hello, I've been getting all sorts of conflicting advice about using slim ducts. House is new construction in Massachusetts. second floor has three smallish bedrooms, about 600 sq ft in total. Heat and cooling load calcs support using an 18k slim to hit the three bedrooms, which aI have a contract with a firm to install. However, a couple of other firms have stated adamantly that the cfm rating of the unit is too low and we won't be happy. Thoughts?

Asked By George M | Apr 18 17
27 Answers

ERV selection

I've been reading, reading and reading about the various ERV options. Once I think I've narrowed it down, I read a new article or a new model has be released. What is the latest thoughts on the ERV market ranking them from best and also value?

Asked By Seth Holmen | Mar 26 17
4 Answers

Dual Stage vs Single Stage Heat Pump

Hello all:

Asked By Adam S | Apr 20 17
2 Answers

Drywall Dust & HVAC Return


I am replacing old wooden wall paneling with drywall.

One of my furnace air return vents is on a wall I am drywalling. The sheetmetal return ducting is flush with the framing, not extended out - when I drywall around it, the metal ducting will be 1/2 inch removed from the grill/register.

My question: what should I do to avoid dust from the cut edges of drywall getting sucked in to system? i.e. all the air coming into this return first passes the cut edge.

Few ideas:
1. extend the ducting 1/2 inch out from the framing so it is flush with the drywall paper face

Asked By Matt Draper | Apr 20 17
6 Answers

Lime in hydronic system

Our low-temperature 9-year-old hydronic heating system, which uses city water in a closed loop with panel radiators, has been accumulating some kind of minerals in a sand-like form. They particularly collect inside the mini flow-meters built into a recently-installed Viega manifold, sometimes clogging them. Possible solutions I've considered include:

1. Flushing the system thoroughly.

2. Using some of the magic chemicals sold for hydronic systems, including cleaning solutions and lime-scale/corrosion prevention solutions.

Asked By Charlie Sullivan | Apr 17 17
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