The short version: Gas tankless handles whole-home hot water for Maryland families with 3+ bathrooms. Electric tankless struggles at family scale because Maryland's cold winter incoming water demands massive electrical capacity — typically a panel upgrade most homes don't have. Electric works beautifully for point-of-use (single sink, detached office, cabin). For all-electric households wanting whole-home hot water, a heat pump water heater (not an electric tankless) is usually the better answer.
The quick comparison
| Factor | Gas tankless | Electric tankless |
|---|---|---|
| Max flow (winter, MD) | 8-11 GPM | 3-5 GPM |
| Whole-home capable (family) | Yes | Rarely |
| Upfront cost (install) | $3,895-$7,495 | $1,500-$3,800 |
| Install requirement | Gas line + venting | 150-200A dedicated circuit |
| Efficiency | 0.82-0.96 UEF | 0.99 UEF |
| Operating cost (family of 4) | ~$185/yr | ~$400/yr (MD rates) |
| Lifespan | 20+ years | 15-20 years |
| Rebates available | Up to $1,400 | Limited |
The flow rate problem with electric
This is the technical issue most comparisons gloss over. Electric tankless units are rated in "max GPM at 35°F temperature rise" — a California-friendly number. In Maryland:
- Incoming water temp in winter: 45-50°F
- Outgoing temp (target): 120°F
- Required temperature rise: 70-80°F
An electric unit rated "7 GPM max flow" at 35°F rise delivers only about 3 GPM at Maryland winter conditions. That's one shower — not one shower plus a dishwasher. You can't physically add more heating capacity without adding more electrical amperage, and at the upper limits you're talking 200+ amps dedicated to a water heater.
Gas tankless doesn't have this problem. A 199K BTU gas unit delivers its rated flow regardless of incoming water temp, because the burner output scales linearly with gas demand.
Install requirements
Gas tankless install needs
- Natural gas service (or propane tank)
- 3/4" or 1" gas line sized for 200K BTU (some older homes need upgrade — $495 on our menu)
- Exterior wall or vent chase for concentric venting (up to 20 ft standard)
- Standard 120V outlet for controls
- Condensate drain tie-in (condensing units)
Electric whole-home tankless install needs
- 200-amp electrical service (100-amp homes cannot accommodate)
- 120-150 amps of dedicated circuit capacity for the unit alone
- 3-4 double-pole 40A breakers typically required
- Heavy gauge wire run from panel to install location
- No venting or condensate (one genuine advantage)
For most Maryland homes, the electrical capacity requirement is the killer. If you have a 100-amp panel, adding a whole-home electric tankless requires a panel upgrade ($2,500-$4,500) on top of the unit install. Total cost starts to rival — or exceed — a gas install without the flow rate benefits.
Upfront cost comparison
For a 3-bath Montgomery County home:
| Configuration | Total install cost | Flow rate (MD winter) |
|---|---|---|
| Gas condensing tankless (our Signature tier) | $5,295 | 10.1 GPM |
| Electric tankless, existing 200A panel | $2,400-$3,800 | 3-5 GPM |
| Electric tankless + panel upgrade | $5,500-$8,300 | 3-5 GPM |
| Heat pump water heater (Pepco rebate available) | $2,800-$4,200 net | N/A (storage) |
The electric-plus-panel-upgrade scenario is typically worse economically than gas AND delivers less hot water. This is why we rarely recommend electric whole-home tankless in Maryland.
Operating cost
Maryland Pepco/BGE electric rates run ~$0.16/kWh. Washington Gas runs around $1.60-$1.80/therm.
Annual operating cost for a family of 4 (~65 gal/day hot water):
- Gas condensing tankless: ~$185/year
- Electric whole-home tankless: ~$400/year
- Gas tank heater (comparison): ~$280/year
- Heat pump water heater: ~$150/year
Over 20 years, operating cost difference between gas and electric tankless is $4,300+. Combined with the upfront cost, gas wins decisively for Maryland families.
Where gas wins
- Whole-home family applications (3+ bathrooms, 3+ occupants)
- Cold-climate installations (Maryland winter)
- Homes with existing gas service
- Higher rebates (up to $1,400 stacked vs. limited for electric)
- Faster recovery and continuous high-flow demand
Where electric wins
- Point-of-use applications (under a single sink, detached guest house, cabin)
- Homes with no gas service and no reasonable path to get it
- Smaller households (single person, couples) with low simultaneous demand
- Apartment/condo situations where venting is impossible
- Higher efficiency on paper (99% vs 96%)
- No venting or condensate lines to route
The third option — heat pump water heaters
If you're an all-electric household or are considering electrification, don't default to electric tankless. A heat pump water heater (HPWH) is usually better for whole-home use:
- 200-300% efficiency (heat pumps extract heat from air, not just electrical resistance)
- Still a storage unit (50-80 gal) but uses 70% less electricity than electric tank
- Pepco offers up to $1,600 rebate on qualifying HPWH
- Maryland statewide electrification program adds up to $15,000 for full-home conversions
We don't install heat pump water heaters — different specialty. For heat pump installs, we refer customers to EDGE Energy or similar contractors in the DMV.
The decision framework
Ask yourself these four questions in order:
- Do you have natural gas service? If yes → probably gas tankless. Move to question 2. If no → question 3.
- Do you have 3+ bathrooms or 3+ occupants? If yes → gas tankless is almost certainly right. If no → read our tank vs. tankless guide first; a gas tank heater may be the better value.
- Do you have a 200A panel with plenty of available capacity? If yes → electric tankless works for 2-bath homes or point-of-use. If no and you want whole-home electric → consider a heat pump water heater instead.
- Is your home all-electric or considering electrification? If yes → heat pump water heater is almost always better than electric tankless.
We only install gas tankless.
Because for Maryland families, that's the answer 95% of the time. Book a consult to confirm it fits your home.