How to install a small water heater?


Our sink and shower are 40 feet from main heater. Can I put a small 2.5 gal heater inline using the hot water line as the source to the sink and shower?

  8 answers
  • Vimarhonor Vimarhonor on Mar 14, 2021

    Hello. At a previous residence we had a water heating device inside our bathroom vanity cabinet adjacent to our shower. It wasn’t that large perhaps looking to the experts of your at the plumbing supply store or plumbing experts here might be able to guide you further.

  • on Mar 14, 2021

    Have you considered an on demand water heater?

  • Seth Seth on Mar 14, 2021


    The unit you are describing will not provide enough hot water fast enough to help with your shower. It will only give you a boost for a few minutes. It will be fine for just your sink. You may want to consider a recirculating pump. Either a model that is installed on your main water heater or a unit that goes under your sink. Make sure the capacity and recovery periods of any changes you make match your needs.

    • See 4 previous
    • Tim Dillinger Tim Dillinger on Mar 17, 2021

      ok thanks for the advice

  • Redcatcec Redcatcec on Mar 14, 2021

    You will have a supply and demand problem with that small of a tank heater. Have you considered a water heating device at the shower with a Point of Use tankless water heater?

  • Mogie Mogie on Mar 14, 2021

    Tankless water heaters heat water directly without the use of a storage tank. When a hot water tap is turned on, cold water travels through a pipe into the unit. Either a gas burner or an electric element heats the water. As a result, tankless water heaters deliver a constant supply of hot water. You don't need to wait for a storage tank to fill up with enough hot water. However, a tankless water heater's output limits the flow rate.

    Typically, tankless water heaters provide hot water at a rate of 2–5 gallons (7.6–15.2 liters) per minute. Gas-fired tankless water heaters produce higher flow rates than electric ones. Sometimes, however, even the largest, gas-fired model cannot supply enough hot water for simultaneous, multiple uses in large households. For example, taking a shower and running the dishwasher at the same time can stretch a tankless water heater to its limit. To overcome this problem, you can install two or more tankless water heaters, connected in parallel for simultaneous demands of hot water. You can also install separate tankless water heaters for appliances -- such as a clothes washer or dishwater -- that use a lot of hot water in your home.

    Other applications for demand water heaters include the following:

    • Remote bathrooms or hot tubs
    • Booster for appliances, such as dishwashers or clothes washers
    • Booster for a solar water heating system.

  • Kathy Gunter Law Kathy Gunter Law on Mar 15, 2021

    I don't think one that small will help with your shower. Consider tankless. Mine is 70 feet from heater to master bath. It takes 2 minutes to get to the shower but once it is there, I have no issue with the water cooling - it is constant supply. I have a regular natural gas heater.

  • This video will show you how to install it:

  • Annie Annie on Mar 18, 2021

    Your best bet is a "On Demand" system for the bathroom