Saturday, January 31, 2015

Facts About Insulation New Hampshire Homeowners Need to Know

Without sufficient insulation, New Hampshire houses are extremely expensive to live in. And since most homeowners know this, it's mind-boggling how many of our houses are still severely under-insulated.

Two weeks ago we talked about how to use the snow melt patterns on your roof to see if it's properly insulated or not. Basically, if the snow there has melted unevenly - and there's no other reason for it, such as sunshine partially blocked by trees - then it's being melted by heat escaping through your roof. Heat is supposed to be inside your house.

It's really quite alarming that in spite of a struggling economy, and in spite of growing public awareness of climate change and its causes, snow melt patterns show up on practically every street in our towns and dot our country roads.

And that's just the roofs. We can only guess how many basements, sills, walls, doors and windows have the same problems. But one thing is clear: when it comes to insulation, New Hampshire houses are generally in bad shape. Which means New Hampshire homeowners are pumping a lot of perfectly-useless carbon into the atmosphere, and paying a lot of money to do so.

How does the heat get out?

There are basically three ways that houses tend to lose heat:
  1. Air exchange: Warm air can leak out of your house, and cold air can rush in. This happens when
    there are gaps in the foundation, around the sills, or at the windows and doors. It also happens if you don't have (and properly use) a double-door entry.
  2. Convection: Since cold air is heavier than warm air, it falls to the bottom of its space and pushes the warm air up. That's why ceiling fans are such an important part of a home heating system. But even if you use ceiling fans, warm air is still going to collect under the roof. And a poorly-insulated roof will suck the heat right out of it.
  3. Conduction: Heat is like water: it always tries to even itself out. If one side of a wall is warm and the other is cold, then the heat on the warm side will conduct through the wall to get to the cold side. Of course, that's a very unscientific way of putting it, but it helps us get a pretty accurate mental picture of what actually happens. The reason insulation works is that some materials conduct heat better than others. Air is a very poor conductor (but it has to be kept from flowing), and therefore most insulation is, essentially, encapsulated air.
So what can you do about it?

Here are some steps you can take to stop paying for the privilege of heating the sky:
  1. Close up your drafts. Start in the basement and go all the way up to the attic. Make sure there are no cracks or gaps in your house. Make sure your roof or attic vents are right for the New Hampshire climate and working properly.
  2. Use two doors. When you enter or exit your house in the winter, do so only through an enclosed (not screened) porch, mudroom or garage. Make sure one door is closed before you open the other. You may be surprised, but a lot of air is exchanged when you use only one door, even if there's no wind.
  3. Insulate. Insulate your foundation, insulate your walls, insulate your roof.
  4. Make sure all your windows and doors are thermal. And then insulate them with thermal drapes or window quilts. Yes, even thermal windows leak heat unless the sun is on them. Make it a habit to close your drapes every night - ideally, as soon as it gets dark out.
  5. Stop thermal bridging. Thermal bridging is heat conducting out through solid building materials in between the pieces of insulation, such as through the rafters of a roof or the studs of a wall. Today's state-of-the-art building methods prevent thermal bridging, but most existing houses need to be retro-fitted to stop it.
With proper insulation, New Hampshire houses can be comfortably heated for a fraction of the 'normal' cost in fuel, money and pollution.

New Hampshire Construction


  1. Great Post. Good points.
    One thing to add, or maybe another article all together: Ceiling fans have two options for directional mode of the motor controlling the blades.
    Switch in one direction pushes air down to the floor and the replacement air is drawn from across the ceiling which come up the side walls. This forces air currents down than out to the main walls and as the air exchanges the cooler air is sucked in at the top of the fan.

    In the other switch setting, air gets drawn up to the fan and than pushes it across the ceiling and down the side walls.

    This is utilized very little and partly because there is confusion as to when to do it. When you blog on this, you could propose that the fan switch be changed when they change their batteries in their smoke detectors, which generally should happen when the clock settings change.

    Keep up the great blogs.

    1. Thanks, Stephen, for such a helpful addition!