Answers to Home Heating and Sealing Questions

Q. What can I put on the windows to keep the heat in the room for the winter and keep the sun out in the summer? Film is not an option, as it will invalidate my window warranty.

A. Whatever you do to reduce the heat gain or loss through those sliders is not going to be cheap. The first suggestion would be to replace the glass IG units in the sliders with IG units that have Low-E or Low-E squared glass. You are looking at probably $100 per pane, or about $1200 for six sliders if you do it yourself. Providing shade for the sliders will reduce the heat gain in the summer, but will not do a thing for the heat loss in the winter.

Q. My sunroom is part of my kitchen. There is no separation and it looks like one big room. I have a problem with the sunroom during the summer and winter. I do have baseboard heat in the sunroom, but when the temps get down into the 30's and below, the heat really struggles. Consequently, it makes the rest of the house cold. I would appreciate any input in keeping the sunroom area warmer during the winter.

A. You are fighting a battle that you are simply not going to win. A sunroom or patio room has a lot of glass, and glass is a poor insulator. You could 'improve' the situation by changing all of the glass to low-E or low-E squared glass, if the windows are dual panes. This would reduce heat transfer through the glass. The best solution would be to wall off the sunroom from the kitchen, putting a 6-foot, 8-foot, or even a 9-foot or 10-foot slider in that wall, and insulating the wall. Just make sure the slider has low-E or low-E squared glass.

Q. The whole house is heated with hot water and a boiler. The boiler/furnace has a chimney that goes up, through the attic and through the roof. We live where it gets to be -10 degrees at times, with very deep snow. I am trying to prevent ice daming, icicles, and water build-up on my roof. The attic floor is insulated, and there is a ridge-vent and the eaves are vented. Would it be wise to insulate it so that heat is not escaping into the attic, causing the roof to melt the snow?

A. The easiest way to demonstrate free and adequate attic ventilation is to dip a straw into a fluid, cover the end of the straw with your finger, and take the straw out of the fluid. The fluid remains inside the straw until you remove your finger from the end of the straw. Adequate free venting is illustrated by removing your finger from the end of the straw, and inadequate free venting is illustrated by leaving your finger on the end of the straw. You can compare this to your situation where there is no snow on your roof covering the ridge vents (adequate free venting) and snow on the roof covering the ridge vents (inadequate free venting).

As far as insulating your chimney flue, it is not advisable to do so. The reasons for this are sizing and flue stack temperature to safely dispose of the gases produced from combustion. The hotter a gas is, the faster it will rise. As the gas produced from combustion rises from either your boiler or your furnace, it draws in a certain amount of fresh air into the combustion chamber. The size of the flue and the temperature of the flue stack gases are designed to provide optimum efficiency. Of course there are other considerations when determining flue stack size, but for this explanation they need not be included. For example, the average efficiency of a furnace is 80 percent. This explicitly implies that 20 percent of the heat produced by the furnace goes up the chimney. This heat or energy is used to safely remove the combustion gases from the structure. The size of the flue and the flue stack temperature determine this. You decide to insulate the chimney flue in the attic. It will affect the flue stack temperature and more than likely increase the temperature, because as the gases rise, they loses temperature. This affects how fast the gases rise. If the flue gases rise faster because of insulating the chimney flue in the attic, then more air will be drawn into the combustion chamber and more heat (energy) will go up your chimney.

Though you remove the flue gases more quickly, the impact of this can be significant. Your heating system is designed to heat your home on the coldest day of the year for your area based on 80 percent furnace efficiency. The increased flue stack temperature created by insulating the chimney flue in the attic extracts more heat/energy than it was originally designed for, resulting in a drop of efficiency to 60 percent. You might not be able to heat your home on very cold days. Another possible result of this is not having enough hot water or constantly running out of hot water when taking showers. Though admittedly there are other possible causes for inadequate domestic hot water supply.

Q.Can anyone suggest a simple way to pinpoint the source of drafts?

A. Natural draft is when warm air cools and becomes heavier than the air surrounding it and falls. Natural drafts are air convective loops and are usually not noticeable or sensed. Natural drafts that people usually sense occur near windows and masonry walls.

Air infiltration resembles the characteristics of a natural draft. It is different because cold air from outside enters the home. Air leakage is the source of air infiltration and most sensible natural drafts. In other words, air leakage within the home results in air infiltration and larger temperature degree differences that make the air convective loops, usually found in homes, noticeable.

The volume of air within the home remains constant, which means that you cannot let air into the house without letting out the same volume of air and vice-versa. Example - if you blow air into a balloon it will get bigger, and if you let air out of the balloon, it will get smaller. Your home cannot get bigger or smaller as air enters and leaves it.

As cold air infiltrates the house, it absorbs the heat from the warm air in the house, thereby cooling the warm air in the house. It is true that the hotter air will rise faster, and that colder air will drop faster. This is what makes natural drafts noticeable to you. Ordinarily, the warm air cools slowly and drops slowly. When cold air infiltrates the house, the warm air in the house cools rapidly and drops rapidly. While a smoke stick or cigarette may help identify a natural draft or air infiltration, the question you have to ask yourself is, "Does it bring me any closer to solving the problem?"

Unfortunately, you are going to find a lot of openings in this ceiling. Examples are whole house fan louvers in hallways, recess lighting, bathroom exhaust fans, attic pull down stairs, etc. For a whole house fan louver in a hallway, tape a piece of plastic over it. Average savings on an energy bill will be 10 to 15 percent. With recess lighting, remove the face cover. You will see a gap between the canister and plasterboard; tape over the gap between the plasterboard and the canister. Savings can be significant depending on the number of recess lights. Remove the cover from a bathroom exhaust and you will find the same thing that you found with recess lighting, and the solution is the same. In addition, clean exhaust fans periodically. In the housing for the fan, you will find a damper. Clean that also so it closes properly when the fan goes off. For attic pull down stairs, stuff insulation between the stair frame and attic framing and tape airtight. There are also good insulating kits for pull down stairs. It is also a good idea to put a latch on the stairs to close it tightly.

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