Electric furnaces are common in Spring, TX and across the Houston area, especially in homes without natural gas. Most are actually air handlers with electric heat strips, paired with a central air conditioner or heat pump. When it is time to replace one, the choices look simple, but getting the size, electrical setup, and blower right makes a real difference in comfort and in your winter electric bill.

This guide explains how to choose an electric furnace: what size you need, what your electrical panel has to support, which features matter, and when a heat pump is the smarter buy.

Quick Answer: How Do You Choose an Electric Furnace?

Start with a heating load calculation to find the right size in kilowatts (kW). Confirm your electrical panel and wiring can support it. Choose a unit that matches your AC or heat pump and fits your installation location, and prioritize a variable speed blower for comfort and efficiency. If your home uses electric heat as its main heat source, compare the cost of a heat pump, which usually heats far more efficiently.

Step 1: Understand What You Actually Have

Many homeowners call it an electric furnace, but in Texas homes it is usually one of these:

•             Air handler with electric heat strips: the indoor unit for your AC, with heating elements added. The most common setup here.
•             Standalone electric furnace: a dedicated heating unit with elements and a blower.
•             Heat pump with backup heat strips: the heat pump does most of the heating, and the strips help during cold snaps and defrost.

Knowing which you have tells you what you are really replacing. Learn more in our electric furnace guide.

Step 2: Size It Correctly in Kilowatts

Electric furnaces and heat strips are sized in kilowatts, not tons. The conversion is simple:

1 kW of electric heat is about 3,412 BTU per hour.

To choose the right size, a technician first calculates your home’s heating load in BTU per hour, based on square footage, insulation, windows, air leakage, and design winter temperature. Then:

kW needed = heating load (BTU/h) ÷ 3,412

Example only: a home with a calculated heating load of 34,000 BTU/h needs about 10 kW of heat. The nearest common size is usually selected.

Common electric heat sizes

Size	Approximate Heat Output
5 kW	About 17,000 BTU/h
8 kW	About 27,000 BTU/h
10 kW	About 34,000 BTU/h
15 kW	About 51,000 BTU/h
20 kW	About 68,000 BTU/h

Why sizing matters

•             Too small: the house struggles to stay warm during hard freezes.
•             Too large: it draws more power than necessary, can require larger wiring and breakers, and may overheat and cycle on safety limits if airflow does not match.

Houston winters are mild most of the time, but events like the February 2021 freeze show why backup heat still needs to be sized for real cold, not just average days.

Step 3: Check Your Electrical Capacity

Electric heat draws a lot of current, which is where many replacements get complicated.

•             Electric furnaces typically run on 240 volts.
•             Larger heat sizes need larger wire and breakers. As a rough guide, 10 kW draws about 42 amps and 15 kW draws about 63 amps at 240 volts, before the blower.
•             The correct breaker and wire size come from the unit’s nameplate ratings, not from a rule of thumb.
•             Older homes with smaller electrical panels may not have room for a larger heat kit without upgrades.

Your installer should confirm panel capacity during the estimate. Electrical work at these loads is not a DIY project.

Step 4: Match It to Your Cooling System

Because most electric furnaces here share the blower and cabinet with your AC coil, they need to work as a system:

•             The air handler’s blower must deliver the right airflow for your AC’s tonnage.
•             The indoor coil should match the outdoor unit for rated efficiency.
•             If you are replacing the AC at the same time, choosing matched equipment avoids compatibility problems, especially with newer refrigerants.

Step 5: Choose the Right Features

Variable speed blower

This is the feature that makes the biggest real difference. A variable speed (ECM) blower uses less electricity, ramps up gradually, runs more quietly, and helps control humidity during cooling season.

Staged heating

Heat strips turn on in stages through sequencers or relays, so the unit does not pull its full load at once. Units with better staging control can deliver steadier heat.

Configuration

Air handlers come in upflow, downflow, and horizontal configurations, and many are multi-position. Your installation location, whether an attic, closet, or garage, determines what fits.

Safety controls

Limit switches and thermal protection shut off the elements if the unit overheats. These are standard, but they should be tested at installation.

Warranty

Compare parts warranty length and registration requirements. Many manufacturers require registration within a set time after installation for the longer term.

Thermostat compatibility

Make sure your thermostat supports your system, especially if you have a heat pump with auxiliary heat. See choosing the right thermostat.

Other Electric Heating Options (and When They Make Sense)

Not every home needs a central electric furnace. These alternatives heat specific areas and are often confused with furnaces:

•             Electric wall heaters: mounted in a wall to heat a single room. Useful for small spaces, but expensive to run as a main heat source.
•             Electric baseboard heaters: installed along the base of walls for room-by-room heat. Easy to install, but costly to operate for a whole home.
•             Ductless mini-splits: not a furnace at all. They are heat pumps that heat and cool individual rooms without ducts, and they use far less electricity than resistance heat. A strong option for additions and garage conversions.

For whole-home heating in a house with ductwork, the real choice is usually between an electric furnace or heat strips and a heat pump.

What About Efficiency?

Almost every electric furnace converts close to 100% of its electricity into heat, so comparing efficiency ratings between electric furnaces does not tell you much. Be cautious of marketing that implies one electric furnace heats much more efficiently than another. Shopping by AFUE rating, which matters for gas furnaces, does not help much here.

What actually lowers your heating cost:

•             A variable speed blower
•             Correct sizing
•             Sealed, insulated ductwork. See duct sealing.
•             A programmable or smart thermostat
•             Switching to a heat pump

Should You Choose a Heat Pump Instead?

If your home relies on electric heat, this is the most important question to ask before replacing anything.

An electric furnace makes heat directly from electricity. A heat pump moves heat from outside into your home. According to the U.S. Department of Energy, heat pumps can cut the electricity used for heating by about half compared with electric resistance heating like furnaces and baseboard heaters.

	Electric Furnace / Heat Strips	Heat Pump
Upfront cost	Lower	Higher
Heating cost to run	Higher	Lower
Cooling	Needs a separate AC	Built in
Performance in mild winters	Good	Very good
Performance in hard freezes	Good	Relies on backup heat strips

For many Spring, TX homes, a heat pump with properly sized backup heat strips gives the best balance. Read heat pump pros and cons.

When to Replace Your Electric Furnace

•             It is 15 to 20 years old or more and repairs are adding up
•             Several heating elements or sequencers have failed
•             The blower motor is failing on an older unit
•             You are replacing your AC, and matched equipment makes sense
•             Your winter bills keep rising

If your furnace just stopped working, it may be repairable. Try our electric furnace troubleshooting guide first.

Questions to Ask Your Installer

•             What heating load did you calculate, and what kW size does that mean?
•             Can my panel and wiring support this size?
•             Does this air handler match my AC or heat pump?
•             Is the blower variable speed?
•             Would a heat pump save me money over time?
•             What warranty applies, and will you register it?

Electric Furnace Installation in Spring, TX

KAC Express helps homeowners in Spring and the surrounding Houston area choose, install, and repair electric furnaces, air handlers with heat strips, and heat pumps. We size systems with a load calculation, check electrical capacity, and give you honest comparisons, including when a heat pump is the better choice.

Learn more about our electric furnace services, heating installation, and heat pumps.

•             Licensed Texas HVAC contractor (TACLB33125E)
•             Open 7 days a week, 7am to 10pm
•             Upfront, flat-rate pricing before work begins
•             400+ Google reviews from local homeowners
•             Financing available

Real customer feedback: “I called at 1:30pm and had my furnace replaced the same day by 5:10pm. Respectful, uniformed crew, and everything was brought up to code.”

Ready to choose a new electric furnace? Call KAC Express at 832-326-5687 or schedule an estimate.

Frequently Asked Questions

What size electric furnace do I need?

It depends on your home’s heating load, calculated from size, insulation, windows, and air leakage. Divide the load in BTU per hour by 3,412 to get the kW needed.

How many amps does an electric furnace use?

It depends on the size. At 240 volts, a 10 kW unit draws about 42 amps and a 15 kW unit about 63 amps, plus the blower. Breaker and wire sizes should follow the unit’s nameplate.

Is a bigger electric furnace better?

No. An oversized unit draws more power than necessary, may need larger wiring, and can cycle on safety limits. Correct sizing gives better results.

Are some electric furnaces more efficient than others?

Almost all convert close to 100% of their electricity into heat. Real savings come from a variable speed blower, correct sizing, sealed ducts, and smart controls.

Is a heat pump better than an electric furnace?

For most homes in mild climates, yes. A heat pump usually costs more upfront but uses much less electricity for heating and also provides cooling.

Can I replace my electric furnace myself?

No. It involves high voltage wiring, large breakers, and matching to your cooling system. It should be installed by a licensed professional.

How long do electric furnaces last?

Many last 20 years or more with regular maintenance. Rising repairs and bills are signs to consider replacement.