Gas Tank Water Heaters
What to know
Budget-conscious homeowners with existing gas service who need a straightforward replacement. Good for homes with moderate hot water demand (2-4 people) where low upfront cost is the priority. Also suitable where natural gas is significantly cheaper than electricity.
Energy-conscious buyers focused on long-term savings, as the low efficiency makes operating costs higher over the unit's life. Not ideal for large households that frequently run out of hot water or homes pursuing electrification. The DOE 2029 standards will significantly limit new gas tank options.
Advantages
- Lowest upfront cost of any water heater type, typically $500-$1,200 for equipment
- Simple, well-understood technology with wide availability of parts and service technicians
- Fast recovery rate, a 40-gallon tank can reheat fully in about 30-40 minutes
- Works without electricity in pilot-lit models, providing hot water during power outages
- Compatible with existing gas infrastructure in most homes without modifications
Trade-offs
- Lowest efficiency of any modern water heater type, with standby heat loss 24/7
- Shorter lifespan of 8-12 years due to constant heating and tank corrosion
- Combustion produces CO2 and carries a small risk of carbon monoxide if not properly vented
- Requires adequate combustion air supply and proper venting, limiting installation locations
- Can run out of hot water during heavy simultaneous use since capacity is limited to tank size
Is this the right type?
40-gallon models
| Model | Brand | UEF | FHR | Height | Est. Cost/yr |
|---|---|---|---|---|---|
| XG40T09HE40U0 | Rheem | 0.65 | 81 gal | 63.75" | ~$358 |
50-gallon models
| Model | Brand | UEF | FHR | Height | Est. Cost/yr |
|---|---|---|---|---|---|
| XG50T09HE40U0 | Rheem | 0.64 | 77 gal | 62.75" | ~$363 |
Installation requirements
What installation involves
Electrical: None for standing pilot models. Electronic ignition models require a 120V outlet. Venting: Atmospheric models use Type B double-wall metal vent pipe with natural draft. Power-vent and direct-vent models use PVC or metal with a fan-assisted exhaust. Proper draft and combustion air supply required per NFPA 54/ANSI Z223.1. Space: Floor-standing tank roughly 20-24 inches in diameter and 48-60 inches tall. Needs clearance from combustible materials per local code, typically 1-6 inches on sides depending on model. Other: Combustion air supply per code, either from the room or via dedicated air ducts. Drip leg (sediment trap) on the gas supply line. Temperature and pressure relief (T&P) valve with discharge pipe to within 6 inches of the floor or exterior. Seismic strapping required in earthquake zones.
Equipment typically costs $500 - $1,200. Installed cost including labor and materials: $1,200 - $2,500.
- Sizing guide Find the right capacity
- Replacement cost guide Equipment, labor, and hidden costs