Wall Furnace Propane Usage
About the Wall Furnace
A propane wall furnace is a compact, through-the-wall heating unit rated at 35,000 BTU that provides reliable heat without ductwork. The unit mounts flush against an exterior wall, drawing combustion air from outside and exhausting gases through a coaxial vent that passes through the wall behind the unit. This direct-vent design eliminates the need for a chimney and makes installation straightforward in homes without existing duct systems. Wall furnaces are commonly installed in older homes, additions, mobile homes, and small apartments where installing central ductwork is impractical or too expensive. A single 35,000 BTU wall furnace can heat 500-900 square feet depending on ceiling height and insulation. Many homes use multiple wall furnaces to provide zone heating, allowing different rooms to be heated independently. The built-in thermostat cycles the unit to maintain the set temperature. Some models include a built-in blower to improve heat distribution.
Annual Propane Consumption Breakdown
The wall furnace consumes propane at a rate of 0.38 gallons per hour at its rated capacity of 35,000 BTU per hour (based on the standard energy content of 91,500 BTU per gallon of propane). Running for approximately 6 hours per day over 6 months per year, the total annual consumption is approximately 419.2 gal.
At the national average propane price of $2.50 per gallon, this translates to an annual fuel cost of $1,047.93, or an average of $87.33 per month. During winter months (November through March), monthly costs are significantly higher at approximately $184.93 per month, while summer months average $17.61 per month. This seasonal variation reflects the concentration of heating demand during the coldest months.
The 250-gallon tank is recommended for homes using only the wall furnace on propane, requiring approximately 3 fills per year. If you have additional propane appliances, calculate your total consumption using our propane usage calculator to determine the appropriate tank size for your combined needs.
Wall Furnace Cost Across Different States
The table below shows how propane costs for the wall furnace vary across representative states. Differences reflect both climate (Heating Degree Days affecting usage) and local propane pricing.
| State | HDD | Price/Gal | Gal/Year | Cost/Year |
|---|---|---|---|---|
| Minnesota | 7,981 | $1.85 | 669.1 gal | $1,237.81 |
| New York | 5,882 | $3.40 | 493.1 gal | $1,676.59 |
| Virginia | 3,960 | $2.75 | 332 gal | $912.96 |
| Texas | 1,711 | $2.30 | 143.4 gal | $329.91 |
| Florida | 683 | $2.95 | 57.3 gal | $168.91 |
| Colorado | 6,128 | $2.55 | 513.7 gal | $1,310.04 |
| California | 2,870 | $3.20 | 240.6 gal | $769.94 |
| Ohio | 5,641 | $2.35 | 472.9 gal | $1,111.34 |
Efficiency Tips for Your Wall Furnace
Maximizing the efficiency of your wall furnace reduces propane consumption and lowers your heating costs. Start with an annual professional service that includes cleaning the burner assembly, inspecting the heat exchanger for cracks, checking the flue and venting system, and verifying proper gas pressure and combustion efficiency. A well-maintained wall furnace operates at its rated efficiency, while a neglected unit can lose 5-10% of its efficiency over time.
Improve your home's thermal envelope to reduce the heating load on the wall furnace. Adding insulation to the attic (R-49 to R-60 in cold climates), sealing air leaks around windows, doors, electrical outlets, and plumbing penetrations, and upgrading to double or triple-pane windows can reduce heating fuel consumption by 20-30% without changing the heating system. These improvements also increase comfort by eliminating drafts and cold spots.
Consider a programmable or smart thermostat that automatically reduces the temperature setting by 8-10 degrees during sleeping hours and when the home is unoccupied. The Department of Energy estimates this simple measure saves 10-15% on annual heating costs. Smart thermostats with learning algorithms and geofencing can optimize the heating schedule based on your actual patterns and even adjust based on weather forecasts for the most efficient operation possible.
Wall Furnace Compared to Similar Appliances
The following table compares the wall furnace to other appliances in the heating category by BTU rating and annual propane consumption.
| Appliance | BTU/hr | Hrs/Day | Gal/Year | Cost/Year |
|---|---|---|---|---|
| Wall Furnace (this appliance) | 35,000 | 6 | 419.2 gal | $1,047.93 |
| Furnace 80,000 BTU | 80,000 | 8 | 1,277.5 gal | $3,193.70 |
| Furnace 100,000 BTU | 100,000 | 8 | 1,596.9 gal | $3,992.13 |
| Furnace 60,000 BTU | 60,000 | 8 | 958.1 gal | $2,395.28 |
| Gas Fireplace Insert | 30,000 | 4 | 239.5 gal | $598.82 |
| Gas Log Set | 40,000 | 3 | 199.6 gal | $499.02 |
| Garage Heater | 45,000 | 4 | 299.4 gal | $748.52 |
Frequently Asked Questions
How many gallons of propane does a wall furnace use per year?
A wall furnace rated at 35,000 BTU per hour, running approximately 6 hours per day for 6 months per year, uses approximately 419.2 gal of propane per year at the national average. This estimate varies by climate: colder states with more Heating Degree Days will use proportionally more, while warmer states will use less. At the national average price of $2.50 per gallon, the annual cost is approximately $1,047.93.
How much does it cost to run a wall furnace on propane?
At the national average propane price of $2.50 per gallon, a wall furnace costs approximately $1,047.93 per year, or $87.33 per month averaged across the year. The monthly cost varies seasonally, with winter months costing more due to increased heating demand and summer months costing less. Your actual cost depends on your state's propane price and your specific usage patterns.
What size propane tank do I need for a wall furnace?
For a wall furnace as your only propane appliance, a 250-gallon tank is recommended. This provides adequate capacity for approximately 4 months between fills. If you have multiple propane appliances, you will need to account for the combined consumption of all appliances when choosing a tank size. Most homes with a furnace plus other propane appliances need a 500-gallon or 1,000-gallon tank.