What are therms and kilowatt-hours?
A therm is a unit of natural gas energy, and it is what your furnace and gas water heater consume. A kilowatt-hour (kWh) is a unit of electricity, consumed by your air conditioner, blower motor, heat pump, lights, and everything else plugged in.
Your bill separates the commodity — the gas or electricity itself — from delivery and fixed charges. That distinction matters when you are evaluating savings: efficiency upgrades reduce the usage portion, and the fixed charges stay regardless.
What are heating and cooling degree days?
Degree days are a measure of how much heating or cooling weather a period contained. They accumulate based on how far the average daily temperature sat from a baseline, so a brutal January piles up heating degree days and a mild one does not.
This is the number that makes bill comparison honest. If January's therms rose 30% over last January and heating degree days also rose about 30%, your system behaved normally and the weather did the rest. If therms rose 30% while degree days were flat or lower, something changed in your house or your equipment.
What causes a genuine spike?
When the weather does not explain it, the cause is usually one of a familiar set.
Common causes of higher usage at the same weather
- A clogged filter forcing longer run times and straining the blower
- Duct leaks in an attic or crawlspace delivering conditioned air outdoors
- A failing or dirty AC condenser coil, so the unit runs longer for less cooling
- Low refrigerant charge from a leak — never a normal condition
- A heat pump falling back to auxiliary electric resistance heat too often
- A water heater scaled with sediment, running longer for the same hot water
- A thermostat schedule that quietly reset after a power outage or battery change
What actually reduces the bill?
In rough order of return per dollar in a typical Des Moines home: air sealing and attic insulation, because they reduce the load your equipment has to meet at all; duct sealing, for the same reason; consistent maintenance and filter changes, which keep equipment operating near its rated efficiency; thermostat setbacks; and finally equipment upgrades.
That order surprises people who assume new equipment is the first move. A high-efficiency furnace in a leaky house still heats the outdoors — it just does it more efficiently. Fixing the envelope first also means the replacement system can be smaller, which costs less to buy and runs better.
Frequently asked questions
Should I compare my bill to last month or last year?
Last year, same month. Iowa's month-to-month swings are so large that comparing March to February tells you almost nothing about your equipment. Year-over-year for the same month, ideally adjusted for degree days, is the comparison that isolates changes in your home rather than in the weather.
Does MidAmerican Energy offer rebates that lower my usage?
Yes — MidAmerican has historically offered rebates on qualifying high-efficiency equipment and tune-ups for eligible customers. Programs and amounts change year to year, so we verify current offerings when we quote and file the paperwork for you as part of the job.
My electric bill jumped in summer but the AC seems fine. Why?
An air conditioner can run poorly without seeming broken. A dirty condenser coil, low refrigerant charge, or a failing capacitor all make the unit run far longer for the same cooling, which shows up on the bill before it shows up as discomfort. A tune-up that measures actual performance will find it.
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