Sample Pages From
ENERGY TIPS: Coping With Energy Problems In A Power Hungry Culture
8
Fresh Air and Exhaust
Source: All That?s Practical About Wood: Stoves, As A Fuel, Heating; How To Make The Best use of Fuels.
Replacing Air
Any form of combustion needs fresh air to continue. By the same token, combustion products, carbon dioxide, carbon monoxide, probably some smoke, cooking fumes, all need a means of exhaust, This brings us to the next topic: how to get rid of exhaust without losing all the heat that usually accompanies them.
Heat costs money and either the fuel or the money may be in short supply.
Heat Exchangers
They are the way of recovering once-used heat that would otherwise be lost. Most heat exchangers require some advance planning and probably some modification.
Consider that a heat exchanger is the key to the process of reusing heat. A heat exchanger is the means whereby heat is recovered before it is lost. They are also a means of getting rid of excess heat.
Heat exchangers take heat from one source and transfer it to another more usable source. That is why an entire chapter is devoted to them.
What we want to do is remove the heat from the exhaust and use it to preheat the incoming air.
Whether the air is used for combustion or breathing, that added heat makes it more acceptable.
Exhausted Air
Normal Air Exchange
Air moves in and out of the house as a regular event and we really don?t want to stop the supply of fresh air. It?s good for us, too. You will find suggestions about how unhealthy a ?tight? house can be. There?s always the threat of naturally occurring Radon gas, too. We want air exchange, only we want it under our terms.
Let?s take an inventory of exhaust air sources:
Exhausts
Go into the bathroom and turn on the fan to get rid of unwanted odors, perhaps the overpowering stench of some ?air fresheners?. Many exhaust fans, as they age, develop a sticky damper that does not fully close. It becomes a leak source. It the damper is too sensitive, the force of warm air may cause it to open and lose some of the heat we paid for to keep the house warm.
Go into the kitchen and turn on the stove exhaust fan to carry away cooking odors. This fan can have damper problems, too. In addition, a kitchen fan may often be left running. If you have a gas flame stove, the fan is absolutely necessary, but it is still taking warm air from the house.
Doorways
Every time someone enters or leaves the house the open door allows the escape of heat, either in during the summer or out during the winter. Doors often have old or faulty weatherstripping, too. An exterior doorway is the greatest heat leak in the house when it is open. Kids only make it leak better.
A clothes dryer uses plenty of fresh air to dry clothes. It is all dumped outside and replaced by cold air usually pulled in from leaks.
How about the pet door? It has its own advantages and necessities, but air escapes every time the door is opened. One solution is not to have a pet with weak kidneys.
If you live out in the country and enjoy the idyllic life, your experience is not complete until a skunk finds that pet door. That poses an extreme ventilation problem.
A wood stove uses great quantities of air for combustion. All of this is exhausted into the great outdoors.
The fireplace is the grand daddy of exhaust systems, because the chimney keeps on working even without a fire, unless the damper is closed each time, and that rarely happens.
A gas fired furnace uses about 17 cubic feet of air for each cubic foot of gas burned. Consider that all of that air goes up the stack. An oil furnace uses even more air.
The bad news is that all of the replacement air pulled into the house is not heated.
The Problem
We need the fresh air.
We desire to have the fresh air tempered by the heat contained in the exhausted air.
We do not want the exhaust openings to give up any unnecessary heated air.
We do not want to create a pressure unbalance that will draw in unheated outside air through random leaks about the house.
We do not want to give up heated air each time an outside door is opened.
Solving these problems leads into the next chapter.
Now for an inventory of fresh air sources:
Leaks
Every outside door is a leak source, especially when it is opened.
Windows leak more according to their age. Older windows do not have the improvements of contemporary windows.
Any exhaust vent may continue to exhaust whether you want it to or not.
Leaks can occur around electric wall switch and outlet boxes unless they have been sealed.
Improperly installed insulation within a wall, under a floor, above a ceiling, may form voids in time and leak as well as if they are a feed through pipes. Poor wrapping of duct work can have the same effect.
Applications
Here are practices you can start now. With a little time, you can make the physical changes.
If you are not using a furnace, cover all vent ports. Even when they are not working, they can funnel off the heat in a room.
Provide a fresh air input port to the outside close to furnaces, fireplaces, stoves. It may be a hole through a wall or the floor. Screen the hole, but no need to worry about air coming in. When a stove is going, it will bring in fresh air from the closest opening.
It would be even better if you could devise a heat exchanger to preheat that combustion air. Read that chapter again.
Storm windows or tape applied around a window will stop the leaks. Many storm window types are available from permanent ones down to a simple tacking of sheet plastic over a window opening.
Doors pose a special problem. The illustration shows a more complicated air trap for a main entry. Other doors may just have a heavy curtain hanging over them. If a door is not used much, it could be taped.
By all means, an exterior door should be weatherstripped. See the following page.
End of excerpt.