Replies

1. 
   BossHog | Apr 12, 2002 07:42pm | #1

   Blowing in batts ? That's a new one.

   I used blown in fiberglass in the spec house I built, both in the walls and in the attic. It was less expensive than batts and had a better R value. I'd definitely recommend it. Never saw any evidence of fiberglass dust in the house area after the drywall was up and things were cleaned up.

   Truss Designer Extraordinaire

2. 
   DHambley2 | Apr 12, 2002 08:25pm | #2

   Dave,

   B-I-B is a high quality method in my opinin. I've had it done in two homes I've built. The first one I lived in for several years and the electric bills were extremely low (also due to R45 in the attic). Just eyeballing the stud spaces before the sheetrock, you can tell how it ssurrounds every junction box and other  things which would normally cause a gap in batts.

   Darrell

3. 
   TLRice | Apr 12, 2002 09:07pm | #3

   Dave,

   I can't add anything about the insulation but a couple of statements you made stirred my curiosity.

   "The house is very tight, but ventilation should not generally be a problem." You said the house has radiant heat and said nothing about AC. Is there any forced air in this house? How is ventilation not generally a concern?

   "Indoor air quality and thermal performance is a concern..." Was the IAQ concern only about the blown glass or a general concern of the occupants?

   A tight house with no mechanical ventilation is a combination that should raise an IAQ concern.

1. 
   Catskinner | Apr 13, 2002 06:15am | #4

   Thanks, all, for the info.

   The major concern here is fiberglass dust inside the occupied space.

   Tim -- no AC, don't need it in this climate. Got four exhaust fans (2 baths, laundry, and range hood), floor plan and operable windows are such that given the client preference for fresh air and the location on top of a ridge with a constant breeze (to say the least) makes me not worry too much about fresh air. Am I missing something?

   All advice welcome and duly considered.

   Dave

1. 
   TLRice | Apr 15, 2002 03:09pm | #5

   Dave, you're probably not missing anything, depending on the environment and how sensitive the owners are to IAQ. Though as you said their only concern was with the fibers.

   However, in an area where no AC is required, I would guess that there is an extended heating season. How many people in northern parts of the country will open windows for ventilation when it is below zero outside? With no controlled fresh air and nothing but exhausts in the house, there will be a negative pressure and inleakage and very dry air coming in. Depending on their habits and how tight the house really is, low humidity may or may not be a concern. This can be irritating to some unnoticeable to others.

   A concern with a tight house that is closed in winter that has gas/oil/lp burning, non-sealed combustion type appliance is the likelyhood of backdrafting flues and draft hoods.

   If the occupants have general IAQ concerns, I would suggest to them that they get an energy recovery ventilator that can provide up to 2 air changes per house of the conditioned space volume. If they are not interested, just make sure to provide enough combustion air to the appliance, if applicable.

1. 
   Catskinner | Apr 16, 2002 03:00am | #6

   Thanks, Tim.

   We're probably heating about 4 months out of the year in this climate, though I expect this house to require less because it's designed as a passive solar house. I've got the gas fired boiler and hot water heater confined to a mechanical room that will get outside air, but there is a gas kitchen range and an electric clothes dryer that will have to get air from somewhere.

   There's no way I'll ever get these folks to go for an exchanger.

   On the basis of your comments, I am thinking seriously about putting a fresh air intake with a damper on it someplace in the house, maybe in the pantry where they'll want it to stay cooler anyway.

   What do you think?

1. 
   TLRice | Apr 16, 2002 03:54pm | #7

   Gas ranges don't use that much (combustion)air and usually, because of the open nature of kithchens, they are not in a "confined" space. The issue is the exhaust. With a standard Broan or the like, its not really much of a concern. With a commercial-like exahust that removes 1000 cfm or so, then it becomes a concern. As with the electric dryer, not all codes require exhaust. If I had an electric dryer, I would vent into the house to retain the heat and moisture, when conditions allow. This cannot be done with lp, gas or oil fired dryers.

   I think the introduction of outside air (OA) into a house is a good idea, but untempered OA can be a problem. In a mild climate, without AC and with plenty of natural ventilation, winter is the only concern. In the winter, no one would like -10 or -20 or even 20 degree air pouring into the house. I would not recommend bringing unconditioned OA directly into the living space.

   The best option is a small ERV, but you said they wouldn't go for that. (A small ERV such as Renewaire's EV130 costs about $850, and could be installed and wired for a total of about $1200)

   Another option would be a tempered OA vent, like a louver with a hot water coil. This would invlove a sleeve, louver, coil, piping and controls and would most likely cost more than the ERV.

   There are pressure activated vents (and reliefs) to allow OA when a pressure differential demands (like a Skuttle), though, I am not familiar enough with these things to give you any good direction.

   All things considered, the simplest (and probably the best) option is to do nothing. You may wish to make your clients aware of the the ERV option, but without their interest (and finacial commitment) that's all you can realistically do.