ideas on how to bring heat down from catheral ceiling and loft above woodstove all in one room
Turtle Pond
| Posted in Energy Efficiency and Durability on
My livingroom has a cathedral ceiling with a loft on one end….heat from furnace or woodstove goes up to ceiling and into the loft…I have a ceiling fan rotating clockwise to bring heat down and a floor fan in loft to blow heat out to living area…
I have thought of lowering ceiling…but that seems a little claustrophobic….
any ideas?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
It's better to mix the hot and room air at the source instead of letting it stratify and then trying to mix this lower grade heat. So I'd have a fan blowing directly across the stove.
Turtle Pond,
You will have stack effect during the winter, but it can be more of a problem if you have a leaky house. Before dropping your ceiling, consider hiring a Resnet rater to evaluate your home. Air sealing and insulation will make your home much more comfortable.
Turtle Pond, the only thing fans really do in an open concept plan is make everyone a little uncomfortable due to blowing cool air around. As Steve says, she best thing you can do is to make your building envelope airtight.
The biggest controllable cause of temperature stratification is air being drawn in low on the building (often at the rim joist area) and exiting at the ridge. The moving air carries heat with it. If you make your house reasonably airtight, you will still be left with a temperature differential due to the fact that warm air is more buoyant than cool air, so the second floor will always be a few degrees warmer, but the difference should be limited to 5-10° at most.
After you solve any air leakage problems, as Steve and Michael have suggested, the next thing you can consider is improving the insulation throughout. As the building becomes better and better insulated, the uniformity of the temperature inside becomes more uniform. Sealing air leaks will have a more dramatic effect and is easier and cheaper to do, but improving the insulation would be the next step if you want to improve it further.
Good point, Charlie, and one I meant to make as well. Even if one does not want to add insulation to walls or roofs, most foundations would benefit greatly from a layer of insulation.
Blower door test rated my house as being too tight...
Also in loft area all along where floor meets wall there is a gap....apparently heat goes in there...travels up inside of wall to roof then goes outside where vents are in roof overhang....I've been told to fill this gap with spray foam...
Also my house wall and roof insulation tested good as well as the doors and windows...
Turtle Pond,
I don't think there is such as thing as too tight. What did the report show? Tight houses need a ventilation strategy. How do you currently ventilate?
Steve, I don’t have results of blower door test but was told that a ventilation system would be a good idea but expensive...so I’m trying to find other ways to get fresh air in that wouldn’t have to be lots of duct work...
There is definitely no such thing as too tight. High performance builders these days routinely get below 0.5 ACH50 (the lowest I've personally seen is 0.2 ACH50), which means the entire house has a composite hole about 2" in diameter. Some builders are getting even lower numbers, which is purely competition at this point.
Your energy auditor may have said your home is tight enough that you should have mechanical ventilation. That's not a particularly tight house, just one that should have mechanical ventilation. If you have a gap where you know heat is being drawn out, your house is not very tight. Did your auditor give you a CFM number with square footage or volume, or an ACH50 number?
I've been in a lot of high performance houses that have very little temperature stratification. One that I designed has four stories including a finished walk-out basement and finished attic. Pretty much the worst case when it comes to stack effect. The builder did an excellent job with air sealing (0.25 ACH50), and it's well insulated, with almost no temperature differential between any level. At the other end of the spectrum, a family member of mine has a manufactured log home, which is very leaky, and has a huge problem with temperature distribution. So I'm not giving theoretical advice.
Michael...I have 1532 CFM AND 21ACH
I SHOULD HAVE ACH.35 and CFM2527
This is my problem along with high ceiling and cracks where heat is going into walls and out roof vents..
And an old oil burner furnace
Turtle, I think you're saying that you have 0.21 air changes per hour of "natural" ventilation, and that you were advised to have 0.35 air changes per hour, which is about what ASHRAE standard calculations often produce. (It varies a bit with building size and occupant load.) That doesn't mean your house is too tight, it just means that you need mechanical ventilation.
Mechanical ventilation is for your health and comfort. The building's airtightness is for thermal comfort, energy savings and building durability.
If you want to reduce your temperature stratification, you need to make your house as airtight as possible (and add a ventilation system), and add insulation as well wherever possible. The age of the furnace will affect your energy bills but won't affect the indoor temperature. You may find some improvement with a redesigned heat distribution system (e.g. relocated or resized ducts in a forced hot air system, or additional baseboard hot water radiators). But the best bang for your buck will be in tightening up your building envelope.
Turtle, just to expand on what others already have said about air leakage, a blower door test gives you just an approximation of what air leakage may be at worst. But leakage depends on wind pressure and temperature difference, being worst when it's windy and bitter cold outside. When it's mild and calm outside, leakage is negligible. So nearly always leakage (thus "fresh air") is all over the place, from maybe far too leaky or even then not "leaky enough" to insufficient for human comfort. Worse, it's uncontrollable. That's why the thinking "the house shouldn't be too tight, it has to breathe" is a building strategy simply does not work. Thus the only strategy that does work is to make it as tight as possible and provide controllable mechanical ventilation.
I agree with the above posters, make the home as airtight as possible to reduce stratification. I would start with a quality job of air sealing and insulating the ceiling, often this is the start of a transformation in comfort.
Hello Dick Russell, have you been monitoring the performance of your house? If you don't mind sharing I would like to hear the latest results. [email protected]