Geothermal vs Natural Gas Calculator

Geothermal vs Natural Gas Calculator

Model the same home on geothermal and natural gas using conditioned area, envelope quality, distribution losses, climate defaults, and emissions factors to compare sizing and seasonal heating energy.

Heating load first The calculator builds a design-day BTU per hour load from area, ceiling height, shell quality, leakage, and temperature difference before it compares equipment.
Two energy paths Geothermal uses adjusted COP and loop conditions. Natural gas uses delivered AFUE after distribution penalties so both systems are compared on the same heating demand.
Useful outputs See geothermal tonnage, gas input size, seasonal kWh, therms, cubic meters, loop extraction, and the annual CO2 difference in one pass.

📏Units and Presets

Preset ready: Mixed Ranch

Preset note: Mixed Ranch starts with a 56 by 34 ft rectangle, 8.5 ft ceiling, mixed climate defaults, and a two-stage geothermal system against a 96 AFUE furnace.

🏠Conditioned Space Inputs

Climate defaults populate design temperature and annual full-load heating hours, then you can fine-tune those values for your location or fuel-use history.

System Comparison Inputs

The geothermal path uses adjusted COP from unit family, loop temperature behavior, distribution penalties, and design temperature lift. Natural gas uses delivered AFUE after the same distribution path is applied.

📊Heating Comparison Results

Design load
0 BTU/h
0 kW heating demand
Geothermal season
0 kWh
0 tons recommended
Natural gas season
0 therms
0 m3 annual gas use
Annual CO2 delta
0%
0 tons per year
Conditioned area0 sq ft
Design temperature difference0 F
Load intensity0 BTU/h per sq ft
Seasonal heating demand0 MMBtu
Adjusted geothermal COP0 COP
Loop extraction0 MMBtu from ground
Geothermal sizing reserve0 tons and 0% aux
Delivered gas AFUE0%
Recommended gas input0 MBH input
Annual emissions0 lb vs 0 lb

Run a Manual J and project-specific loop design before locking in final equipment sizes.

🧰System Quick Specs

3.8 COP
Single-stage geo
Stable baseline capacity with the widest cycling swings. Best when loads are simple and controls are basic.
4.2 COP
Two-stage geo
Common residential sweet spot for solid winter COP, better part-load control, and straightforward ducted retrofits.
4.8 COP
Variable geo
Best seasonal efficiency and shoulder-season modulation. Strong option when load swings and humidity control matter.
4.5 COP
Hydronic geo
Pairs well with radiant slabs and lower supply temperatures, which helps geothermal avoid high winter lift penalties.
80 AFUE
Basic gas furnace
High reserve and lower venting complexity, but more fuel input per delivered MMBtu during the heating season.
92 AFUE
Two-stage gas
Better seasonal combustion efficiency and cleaner part-load operation for medium-sized homes with existing ducts.
96 AFUE
High-eff gas
Typical condensing target for performance-oriented retrofits where natural gas remains the primary winter heat source.
97 AFUE
Modulating gas
Best natural-gas efficiency path in this tool, with lower reserve margins because staged modulation handles shoulder conditions.

📋Climate and Distribution Reference

ClimateDesign TempHeat HoursTypical Use
Mild winter30 F1100 hShorter season, smaller gas and geo equipment
Marine24 F1350 hModerate design load with steady shoulder runtimes
Mixed climate18 F1650 hBalanced benchmark for common retrofits
Cold climate5 F2100 hLong heating season where loop type matters more
Very cold-8 F2600 hAuxiliary share becomes more likely on geo sizing targets
Hot-humid36 F900 hLower winter load and warmer entering water

These defaults are editable in the calculator when you know your exact design-day temperature or full-load heating-hour estimate.

🛠Distribution Effect Guide

Distribution PathGeo COP EffectGas AFUE EffectBest Fit
Radiant floor or panel+6%BaseExcellent for hydronic geothermal
Sealed short ductsBaseBaseStrong neutral benchmark
Attic ducts-5%-3%Retrofits needing duct sealing
Crawlspace ducts-3%-2%Moderate winter penalty
Hydro-air coil-1%-1%Good hybrid hydronic match
Fan coil zone-4%BaseUseful on small zoned additions

📐Common Project Benchmarks

ProjectAreaGeo SizeGas InputHeat Demand
Tight townhouse1400 sq ft2.5 tons46 MBH31 MMBtu
Mixed ranch1900 sq ft3.5 tons74 MBH53 MMBtu
Radiant slab build2100 sq ft3.0 tons63 MBH45 MMBtu
Older cold colonial2400 sq ft4.5 tons111 MBH91 MMBtu
Large open plan2600 sq ft4.0 tons94 MBH72 MMBtu

💡Use Notes

Check distribution before equipment

Attic and crawlspace ducts can erase a meaningful share of the performance gap between geothermal and natural gas. If you seal the distribution path first, both systems usually size smaller.

Use load coverage intentionally

Many geothermal systems are not sized for 100 percent of the rarest winter hour. A 90 to 95 percent target can still cover most annual heating while limiting auxiliary runtime.

Choosing between geothermal energy and natural gas depends on several things. Almost always geothermal solution is the best. It forms the most efficient way heat and cool.

Such nets reach really bigger efficiency than the best gas boiler on the market. Although natural gas itself is strong, other fossil fuels fail fast. Burn fuel in gas boiler generate heat, that later is distributed through the house.

Geothermal or Natural Gas: Which Is Better?

That is less efficient than simply transfer energy. Geothermal heat pumps reach around 500 percent efficiency, what surpasses everything else.

Install geothermal heat pump cost relatively a lot. In some places lacks enough territory for such system. Ducted heat pump could require centuries for make up in 15,000 dollars.

One geothermal installation arrives in 127,000 dollars, but 30,000-dollar credit lowers that. Other case shows geothermal systems in less than 20,000 dollars after 10,000-dollar builder discount and tax return. Natural gas commonly is the cheaper chance.

Bring it to home cost around 13,500 dollars of the current end of line. Connect fee stores 1,650 dollars for the first 100 feet and 4 dollars each extra foot. Two years before you paid 5,200 dollars for gas half a mile away.

Natural gas could seem clear, but geothermal happen 22 until 28 percent less cost each term unit for heating.

Geothermal systems operate without problems. Existing ground loop probably will serve several decades. Only parts require refill.

Internal gear lasts 25 years or more, during exterior last 50 years or more. Geothermal can ensure 70.8 percent of warm water. That lowers the expenses for water-warming in 60 percents.

Annual cost for warm water falls from 433 to 173 dollars. In usual houses with gas heat you install standard AC unit for cooling. Geothermal uses earth heat for produce electricity, so it is renewable.

About carbon intensity it a lot surpasses natural gas.

Geothermal vs Natural Gas Calculator

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