RESIDENTIAL WATER HEATING

For 20 years Liquid Solar has been designing and installing innovative and efficient residential water heating systems.

CHOOSING AN EFFICIENT WATER HEATER

Choosing an efficient water heater can challenging, whether replacing a water heater on an existing home or designing a new home.

NEW CONSTRUCTION

  • If going all-electric a heat pump water heater is probably the best fit.

  • An electric on-demand water heater  may make sense if space for mechanical area is limited or demand for hot water is high.

  • If home will have intermittent periods of high demand but maximum efficiency is desired, then a combination system with a heat pump water heater and a small on-demand electric as a booster for periods of high demand.

  •  If no solar, a heat pump water heater may still be good choice; or natural gas/propane is preferred, then an on on-demand gas is the way to go.

EXISITING HOMES/SMALL BUILDINGS

Generally when plumbers are replacing existing water heaters on older homes they will recommend the least efficient, lowest cost water heaters.  The tables below will help you determine the most efficient options, starting with ID of your existing one

WATER HEATER COMPARISON CHART - CLICK IMAGE TO ENLARGE

TYPES OF WATER HEATERS (3.21.25: more coming soon!)

Heat Pump Water Heater

Heat Pump Water Heaters are good for new construction or existing home/retrofit/ replacement

  • Pros

    • The most efficient water heater, period

    • Reliable proven technology

    • Available in 50, 65 and 80 gallon sizes

    • Very D-I-Y friendly

    • May qualify for federal tax credits

    Cons

    Not a good choice in small closet or small space (need at least 50-100 square feet; unless ducted)

    Not recommended for extremely high hot water demand.

    Older model were noisy; new ones better but still not best directly adjacent to bedroom

    Some plumbers will claim “they don’t work” (wrong) and will not want to install; may need to order online

    • Approximately $2,500 to $4,000 installed and not including tax credits (City of Bozeman offers $500)

    • Steibel-Eltron Accelera series (for some reason not Energy Star rated); Bradford White  Aerotherm series.

    • Other brands like AO Smith, LG, Rheem seem good to

Basic Electric Tank Style Water Heater plus Solar PV

Heat Pump Water Heaters are good for new construction or existing home/retrofit/ replacement

  • Pros

    • The most efficient water heater, period

    • Reliable proven technology

    • Available in 50, 65 and 80 gallon sizes

    • Very D-I-Y friendly

    • May qualify for federal tax credits

    Cons

    Not a good choice in small closet or small space (need at least 50-100 square feet; unless ducted)

    Not recommended for extremely high hot water demand.

    Older model were noisy; new ones better but still not best directly adjacent to bedroom

    Some plumbers will claim “they don’t work” (wrong) and will not want to install; may need to order online

    • Approximately $2,500 to $4,000 installed and not including tax credits (City of Bozeman offers $500)

    • Steibel-Eltron Accelera series (for some reason not Energy Star rated); Bradford White  Aerotherm series.

    • Other brands like AO Smith, LG, Rheem seem good to

On-Demand (Tankless) Water Heaters (gas)

Heat Pump Water Heaters are good for new construction or existing home/retrofit/ replacement

  • Pros

    • The most efficient water heater, period

    • Reliable proven technology

    • Available in 50, 65 and 80 gallon sizes

    • Very D-I-Y friendly

    • May qualify for federal tax credits

    Cons

    Not a good choice in small closet or small space (need at least 50-100 square feet; unless ducted)

    Not recommended for extremely high hot water demand.

    Older model were noisy; new ones better but still not best directly adjacent to bedroom

    Some plumbers will claim “they don’t work” (wrong) and will not want to install; may need to order online

    • Approximately $2,500 to $4,000 installed and not including tax credits (City of Bozeman offers $500)

    • Steibel-Eltron Accelera series (for some reason not Energy Star rated); Bradford White  Aerotherm series.

    • Other brands like AO Smith, LG, Rheem seem good to

TYPES OF WATER HEATERS

On-Demand (Tankless) Electric Water Heaters These are best for new construction because of the high a

On-demand electrics are best for new construction because of the high amperage required (the smallest ones require two 45 amp breakers) but can work well on older homes depending on the situation if the electrical service is at least 200 amps.

  • Pros 

    • very efficient (no storage of hot water)

    • very compact

    • can satisfy very high hot water demand situations if sized properly

    • Durable and long lasting if properly maintained (hard water is the concern)

    • D-I-Y friendly

    • low cost 

     

    Cons

    • not good where water is very hard (or requires water treatment system which is good anyway)

    • some plumbers will claim “they don’t last” (wrong)

    • approximately $1500 to $2500 installed including wiring/electrical

    • Steibel-Eltron Tempra series (many sizes); also Bosch, Eco-Smart and Rheem 

    • Available on-line only

Wall Mounted Compact Tank Style Water Heaters (electric)

These are very common in Europe where they will put several in house and close to each point-of-use. But can be used as whole-house water heaters where demand is low, or as a backup where water is pre-heated by solar or by an A2W heat pump. 

  • Pros 

    • Compact; can be mounted high on wall as the connections are on bottom of water heater

    • Only requires 15 amp breaker

    • Easy to adjust dial for water temp (from 80f to 160F)

    • Easy D-I-Y

    Cons

    • Slow recovery rate once water is used up 

    • Water output is limited if this only source of hot water (but still fine for small homes)

    • Most plumbers don’t know about them and need to order online

    • Approximately $1,500 installed.

    • The only company that brings these in from Europe is Stiebel-Eltron 

    • PSH20 Plus is 20 gallons and the PSH30 Plus is 30 gallons.  

    • Available on-line only

Solar Hot Water (solar thermal or solar heating)

SOMETHING HERE

  • Pros

    • Very efficient and can provide 70% of annual hot water demand 

    • Excellent where there is high demand for hot water

    • System can be expanded to tie into space heating; excellent fit with Arctic heat pump systems

    • Not net metered or tied to utility grid; not subject to utility monitoring 

    • Reliable and long-lasting if well designed and installed  

    • Great for off-grid homes

    Cons

    • No longer qualifies for solar tax credits

    • Installers hard to find (but can be D-I-Y friendly)

    • $6,000 to $10,000 +

    • Liquid Solar are dealers for Sun Earth and we believe they make the best hardware