Why Is My Heating Bill So High? (The Answer Usually Isn't Your Furnace)

Short answer: if your heating bill jumped and your furnace is working fine, you are almost certainly paying to heat air that is leaking out of the building. In most Nebraska homes the furnace is not the problem. The problem is that warm air escapes through the attic, the rim joist and the crawl space faster than the furnace can replace it, so the furnace runs longer to hold the same temperature. Sealing those leaks lowers the bill in a way that turning the thermostat down never will.

Every November we get the same phone call. The first real heating bill of the season shows up, it is a lot higher than anyone expected, and the question is whether the furnace is going out.

Usually it is not. Here is how to tell what you are actually dealing with.

What makes a heating bill go up when nothing changed?

Three things drive the number on that bill: how cold it is outside, what you pay per unit of fuel, and how fast your house loses the heat you just paid for.

You cannot control the weather and you cannot control the rate. The third one is the only part of the equation that is yours, and it is the one almost nobody looks at.

A house that leaks air has to be reheated constantly. The furnace cycles on, warms the room, the warm air rises and pushes out through gaps in the attic and the rim joist, cold air gets pulled in low to replace it, and the furnace kicks on again. That cycle runs all winter. The thermostat reads 70 the whole time, so nothing looks wrong, and the bill quietly reflects every one of those cycles.

How can I tell if my house is leaking air?

You do not need equipment for the first pass. Walk the house on a cold, windy day and look for these.

• Cold floors. Especially over a crawl space or an unfinished basement. Cold floors mean cold air underneath.
• One room that never gets warm. Usually a room over a garage, an addition, or a bonus room.
• A furnace that runs almost continuously but never quite satisfies the thermostat.
• Drafts near outlets, baseboards, and where the wall meets the floor. Hold the back of your hand there. If you feel movement, air is coming in from outside.
• Dust collecting fast. Air moving through the building carries dust with it.
• Ice dams or heavy icicles on the roof edge. That is heat escaping into the attic.

We went through the usual suspects in more detail in why is my house so drafty.

Isn't the fix just more insulation in the attic?

Adding insulation helps, but on its own it is often disappointing, and this is the part that surprises people.

Insulation slows heat moving through a surface. It does not stop air moving through a hole. Blow another foot of loose fill over an attic that has gaps around the light fixtures, the chimney chase and the attic hatch, and the air still goes straight through. You have slowed one kind of heat loss and done nothing about the other.

That is why a house can have plenty of insulation in the attic and still feel drafty and still cost a fortune to heat. We laid out the difference in air sealing versus insulation.

Closed-cell spray foam does both jobs in one pass, which is why it tends to show up on the bill faster than anything else we install. It expands into the gap, cures solid, and becomes the air barrier and the insulation at the same time.

Where does the money actually leak out of a Nebraska house?

In order of how often we find it, and roughly in order of what it costs you.

1. The rim joist. The band of framing at the top of the foundation. It is usually either empty or stuffed with a fiberglass batt that air moves right past. It is the cheapest high-impact job we do. More on rim joists here.
2. The crawl space. A vented crawl space is an open hole under your floor. Sealing it changes how the whole main floor feels.
3. The attic plane. Every penetration through the ceiling, plus the hatch.
4. Bonus rooms and additions built onto the original structure, where the framing joins up awkwardly.
5. Attached garages, which pull cold into the rooms next to them.

How much will this actually save me?

We are not going to quote you a percentage, because anyone who does is guessing. Savings depend on the age of the house, where the leaks are, what fuel you burn, and how you live in the space.

What we will tell you is this. The homeowners who see the biggest change on their bill are the ones whose crawl space or rim joist was wide open, because that is a large area of raw heat loss sitting in one place. Those jobs are also usually the least expensive ones on the list, so the payback is the fastest.

When we come out we will tell you which of your problems is the expensive one, and whether it is worth the money to fix the rest. If one job gets you most of the way there, we will say so.

If you want the price ranges first, we published them in what spray foam insulation costs in Nebraska.

Frequently asked questions

Should I replace my furnace to lower my heating bill?

Not before you know how much heat the building is losing. A new high-efficiency furnace in a leaky house still has to heat the outdoors. If the shell is sealed first, you may find the furnace you have is sized just fine.

Does turning the thermostat down help?

A little, and it costs you comfort to get it. A leaky house loses heat in proportion to the difference between inside and outside, so dropping it a few degrees shaves a little off. Sealing the leaks changes the rate of loss itself, which is a much bigger lever.

Will new windows fix a high heating bill?

Windows are usually a small share of the total loss, and replacement windows are one of the most expensive things you can buy per unit of savings. Most houses we look at would get more out of a rim joist and crawl space for a fraction of the cost.

Can you do this in the middle of winter?

Yes. Rim joists, crawl spaces, basements and attics are all interior work, and we spray through the season. Winter is actually when it is easiest to find the leaks, because you can feel them.

How long does the work take?

Most residential jobs are one day. Larger whole-house projects can run two. The foam cures quickly and the space is usable the same day in most cases.

Find out where your money is going

If your bill went up and you cannot explain it, the answer is somewhere in the building, and it is usually in one of five places. We will come look, point at the actual spots, and give you a number.

The estimate is free and there is no pressure attached to it.

Request a free estimate or call us at 402-269-7058. We serve Syracuse, Lincoln, Nebraska City, Palmyra, Unadilla, Avoca, Elmwood, Weeping Water, Eagle, Louisville and the surrounding area.