Do you ever wonder why your bathroom is colder than your bedroom? Or why there is a slight breeze when you walk past your fireplace? Most likely the reason is because of thermal bypasses, translated into non-scientific speak, holes in your house that let the heat out or in the summer let the heat in. In some cases they’re not holes but just really good paths that conduct heat from the inside of your home out like a section of missing insulation. Traditional construction techniques don’t always keep a house sealed. With a little investigation you might find large openings, yes I’ve removed insulation to find that I could see sunlight coming through a wall, or ones that are just too small to notice but still add up to a lot of loss. It’s like trying to carry water in a bucket full of holes, you can do it but there’ll be a lot of waste. The building envelop of your house is like that bucket, it includes the walls and roof, simply anything that separates you from the outdoors. If there is a thermal bypass within the buildings envelope, there is an inadvertent hole letting the heat escape.
Everyone desires their dream house with a jetted tub, skylights and the ever popular complex roof lines and bump outs; however these are the things that can create these thermal bypasses. During the housing boom quality could sometimes be traded for speed. Think of your house as a box that contains heat and everywhere that there is a hole in that box, windows, doors, pipes, electrical outlets and so on is where you’ll need to look for leaks. The leak could also be in the form of missing insulation allowing for heat to be conducted quickly out of your home. When you put that cardboard sleeve on your coffee cup it’s easy to hold because it is insulated from your hand. When you touch the cup directly the heat transfers quickly and you want to drop it. It’s the same with your house whether the builder or someone else doing maintenance created the situation it’s still costing you money and comfort when that heat is lost. An energy auditor can do a blower door test as well as use infrared cameras to find those leaks for you. Since many such areas for leaks are encased inside your walls this might be the only way to find them.
Thermal bypasses can be found near stairs or bathtubs built into exterior walls, zero clearance fireplaces, skylights, ceilings over porches, and knee walls. If you have any of these in your home, it’s worth checking them out. If you find an area where you tend to have lots of spiders, they just might be entering through a small opening and if it’s a mouse, well they need a bigger opening. If you wish to learn more about this issue take a look at Erik North’s article about major thermal bypasses or possibly have your house energy audited, you never know what could be behind those walls: Major Thermal Bypasses the big holes in your house
For how to fixes see: Home Insulation and Air Leaks