That house doesn't have enough insulation. How did I know that?

How do you know if there is enough insulation to keep heating dollars from flying out of the top of your house? On days like today, it is pretty easy. It is January. We had snow about a week ago. Today, it is 44 degrees out.

Today, while I was driving through Needham, I noticed a house with significant snow cover on the roof. The house with a full complement of snow stood out. Other houses on the same street had bare roofs. That house has good insulation.

Sunlight melts snow, eventually, even when the air is below freezing. But, most of the time, snow is melted from heating dollars at work. House heat will rise right through the roof unless there is insulation to stop it.

Insulation on the floor of an unfinished attic is a great energy saver. It is a no-brainer that pays back fast. If you have a finished attic space, insulation is just as important. However, it is a little trickier because you need to insulate and ventilate in the roof space above the finished rooms. Fresh air needs to get into the bottom side of the roof surface and a blanket of insulation needs to stop the house’s heat from passing up through the roof. A baffle between the air space and the insulation is the way to do that. Failure to insulate can lead to a nasty mold problem. (More about that another day.)

If you are a buyer, what should you look for? On a day when snow is on some rooftops, look at a house you are considering. If it is the only one without snow, there is not enough insulation. If you can see the lines where the roof rafters are causing less snow melt, there is not enough insulation. (It will look like stripes of deeper snow with patches of less snow in between.) But, if every house on the block has melted snow, it may be a sunny spot or the day is warm enough to melt most snow.

As an aside, sky lights melt snow fast because they insulate much less than roof material. Consider getting an insulated shade for your skylight.

Easy ways to waste your heating dollar

Today, I saved my tenants a hundred or more dollars. This is how it happened: A couple of weeks ago, one of my tenants reported that his window sash didn’t stay up. I asked my tenants to check all their windows so that I could get all the repairs done at once. Please open and close and lock all your windows. Let me know which ones don’t work.

When I came in today, almost all the windows were unlocked. I locked them. Thus, I decreased the cold air flow significantly. My tenants are like most people. Most people don’t know that these windows are not really sealed until they are locked.  

On the way out, I noticed they put their boot mat over the air intake for their furnace. This is also something most people don’t know about, until it happens to them. By covering the intake, the furnace has to work harder to get air in. The intake grate is usually bigger than the grates that the heat comes out of. They are often in hallway (which make them tempting for places to put boots.) If the furnace is blowing and the grate is not getting hot, it could be an intake grate. (It could also be a duct that is blocked off.) Blocking this grate decreases the efficiency, at least, and can cause worse problems if the air is cut off too much for too long.

This happened before. That was with the old furnace and old tenants. They had a rubberized mat over the whole intake grate. That caused the furnace to stop working. The HVAC guy showed me what they were doing and tuned up the furnace while he was here.  Problem solved. Until today.

Another side-effect of putting your boots on the intake grate is that, on rare occasions, it can make your house smell like au de roasted boot. I didn’t smell this first-hand -- so it may be an urban legend -- however, this is the story I heard:

There was a house that had a bad smell. Sort of briny. The family cleaned everything, but the smell persisted. Eventually, they went to get their heating ducts cleaned. The duct cleaning crew told them that they shouldn’t store sneakers on the intake grate. That was probably to source of the smell. They cleaned the ducts anyway. Afterwards, the smell was gone.

The takeaways:

Lock vinyl windows in the winter for better efficiency.

Keep mats, furniture, and shoes off the intake ducts for furnaces. The machine needs air flow to function properly.