Community: Mechanicals

Much of the value of this site is the pooled experience of members and their willingness to share it. This page offers a Community area formatted for Questions & Answers dedicated to Mechanicals. Other topics appear to the right.

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27 Answers
HRV or ERV in cold climate?

I'm building a well insulated house (R-40 walls and R-60 roof) in a 9500 heating degree day climate (Upper Michigan) and will not have air conditioning. Most sources seem to suggest an HRV in this situation but I have had several people recommend an ERV as the better choice. What would I gain with an ERV in my situation, I thought ERVs were for air conditioning climates?

Asked By Donald Lintner | Aug 11 09
9 Answers
Can I get away with radiant floor heat, some ducted dehumidification for summertime, and spot ERVS in a large-ish new home in Virginia?

I live in the foothills of the Appalachians.

Asked By Neal King | Sep 1 10
19 Answers
How do I reconcile an electric, tankless water heater and low flow faucets?

I have installed my first tankless electric water heater. It is an RP27PT single phase Powerstream Pro Redring, made by BBT North America Bosch Group. It works fine at the washing machine, or, if you turn on multiple valves but any one, by itself, will not activate the heater. After a couple of hours on the phone with tech support, I believe our low flow shower valve, vanity faucet or kitchen sink faucet, do not allow enough volume of water to pass through the heater to activate it. We have 45psi water pressure at the heater.

Asked By David Anderson | Jun 19 09
15 Answers
Smallest ERV unit vs. RecoupAerator

We have a small home (1320 sq ft) in SW Wisconsin, and we are bermed into the hill and using a tight envelope with passive solar, high thermal mass and radiant floor heat (that we may not use very much).

We are going to put in the ductwork for an ERV because of what I've read about air quality and our concerns about humidity control.

Asked By sheri | Jul 28 10
10 Answers
Most energy-efficient ERV?

I'm planning a net-zero energy home built from SIPs, and am trying to size my PV system accordingly. Unfortunately, I'm finding that the ERV that the home needs eats electrons with relish (one model, if run at the highest setting, will consume about 6 kWh per day if it runs continuously). That said, I don't understand the workings of an ERV to know if it does run continuously or cycles, or what the average daily electricity consumption is. I'm hoping folks on this forum can share their insights.

Asked By Claire Anderson | Sep 16 09
13 Answers
Seeking an air-to-water heat pump

I'm looking for an air-to-water heat pump and feedback from those who've used them. We have a LEED for Homes project in Victoria, BC, perfect climate for heat pump, affordability of project prohibits groundsource for 36Kbtu heat loss of 1800 ft2 home and for optimal comfort, low temp/efficiency, to avoid ducting we're selected hydronic in-slab for heating distribution thus standard air-to-air heat pump is a no-go.

Asked By Allison Ashcroft | Jul 28 09
8 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
30 Answers
Best Ventilation Bang For The Buck In My Climate

I am in the process of a planning a new house. Approximately 2,000 - 2,500 square feet. ICF construction with sealed attic (spray foam under roof deck). I expect the house to be tight and want to make sure I provide for proper ventilation. I've read about the various options and I am now trying to determine what would be the best bang for the buck in my climate. The house will be built in the Lubbock Texas area (360 miles west and slightly north of Dallas). Climate is fairly dry.

Asked By Donald Cullon | Feb 24 10
12 Answers
Bath fan controls

As part of a remodel project I've been asked to install new fan controls for two bathrooms, each with its own fan. The existing controls are simple toggle switches, and apparently at least one occupant (a teenager who is otherwise a straight-A student) cannot be persuaded to switch the fan on during lengthy showers. In the past I have installed 5-10-20-30 timer switches, and like those in my own house, but I've been able to get people in the household to use the fans every time.

Asked By David Meiland | Jul 16 10
1 Answer
Does anyone have any experience with "SLIM JIM" lake plate exchangers?

I am building a new floating home in the Fraser River in BC. I have a plan to install a Geothermal closed loop heating and cooling system that will utilize (2) 2 ton "Slim Jim" lake plate exchangers attached to the float below the water line. The temperature of the river historically ranges between 1 degree and 20 degrees celcius through the year.
River current should make these exchangers operate more effectively than in a typical lake or pond installation.
I wonder if anyone has any experience with these plates in a river installation (or any other for that matter)?

Asked By Jim Dorval | Jan 16 10