When it is cold outside, I mean subzero cold outside, how is it that one room in my house is always much colder than the rest of my house? Well, there are a couple basic things to look at before you too far down the rabbit hole.
Make sure the heating registers are open
Make sure the windows are closed
Make sure there is some air coming out of the registers
Ok, now that we have ruled out the obvious, let’s talk about other options.
1. Duct system
We know that it is not the furnace because the rest of the house is cozy but it could be how the heat is distributed to the house through the ducts. A lot of times the cold room will be the furthest from the furnace and if that is the case, look to the ducts as the culprit. The heat must travel a long way and often has to take many turns which reduces the amount of heat getting to the room. If that is the case, then a booster fan can be a good solution. This is where a technician will install a mini fan inside the duct that turns on when the furnace blower motor turns on. It is not really a DIY project and will run you about $500.00.
Have you ever heard of balancing a duct system? It is when a technician will measure how much air is coming out of the vents and then adjust the dampers and furnace fan speed to make sure the vents are getting the correct amount of air. This service will also fix any problems with improper duct design and flow. The problem is not many technicians are trained in balancing, especially residential contractors. If you do find one that offers the service, it should be about $300-$600 per furnace.
Another possible problem is:
2. The insulation.
The insulation controls how fast the heat leaves the room. The more insulation the slower it escapes. Check the wall insulation, floor insulation (if applicable) and attic insulation. The cost to add insulation really depends on the location and the material but you can use $1.00 per square foot as a rule of thumb.
The most common reason why one room is colder than the others is a combination of both. Your house is a system and your furnace and insulation work together to make your home livable.