Water Heater Talk: Which is Right for Your Tiny House?

One of the questions I get asked most frequently is about which water heater is best for a tiny house. Tankless versus tank, propane versus electric? The possibilities are endless and there is no straight answer. Your water heater is one of the most important aspects of your home!

First you need to answer some questions mostly about your tiny house but also about yourself (or the person/people that plan to live in it).

  • Will you be connected to electricity or run on solar power?
  • Will you be traveling frequently or plan to stay in a more permanent location?
  • What is your current hot water usage?
    • Think about your kitchen and bathroom sink, shower or tub, washing machine and dishwasher. You may not be using all of these appliances in your tiny house or you may be using all of them.

Knowing the answers to these questions will help you decide a water heater based on your personal needs. It’s okay if you can’t answer them right away.

Plumbing is, of course, the first step to getting a water heater. Ethan from TheTinyHouse.net wrote an excellent article about tiny house plumbing and how to get water in and out of your tiny house.

Indoor vs Outdoor

Climate Control

Outdoor water heaters will have different needs than indoor heaters. Insulation is needed if your water heater will be outdoors so it does not get damaged by the freezing temperatures. Tiny House Giant Journey wrote an article about their water heater and the results of freezing temperatures.

Propane tank blankets can be used to help fight freezing temperatures. Plan to purchase one if you will have your propane outdoors.


Indoor units will either vent out of the floor or wall. They must pull fresh air in from the outside and vent out combusted propane gasses. Most RV models will vent out of the floor which may look better (not having a vent out the side of your tiny house) but are generally more expensive.

Residential vs RV

Warranty is Key

Always check on the unit’s warranty before you purchase or install it yourself. Some companies will not honor a self-installation (requires a professional to install it) while some residential units are not covered by being in a tiny house. Tiny-Project.com talks about their experience with a Rheem/Richmond RTG-64 water heater warranty.

[beautifulquote align=”full” cite=”Tiny-Project.com”]We chose this model. I did not know this when purchasing, but Rheem’s installation guidelines specifically state that the product is not intended for RV or mobile home use — they will not honor the warranty. … This is likely the case for all residential models, with the possible exception of those from Eccotemp, who is more tiny house friendly (based on the anecdotes I’ve heard).[/beautifulquote]

Size and Cost

Residential units tend to be a bit more cost effective, but RV units tend to be smaller and more compact. Again, before purchasing residential, check with the warranty to ensure it will be covered if installed in a tiny house.

Gallons per minute or GPM is another figure to calculate in how much hot water you need to produce at any given moment. CompactAppliance.com gives a great rundown on how to measure your appliances in GPM. This, in turn, helps you understand what size tank or tankless water heater you need to meet your needs. The great part about this GPM table is you can also learn how to offset the use of water and opt for something smaller. An example would be not taking back-to-back showers or running the washing machine in the opposite part of the day from your shower.

Table GPM averages courtesy of CompactAppliance.com

Fixture Average Flow GPM Average Temp.
Tub 4.0 GPM 102°F
Shower 2.5 – 3.0 GPM 104°F
Washing Machine 2.0 GPM 120°F
Dishwasher 1.5 GPM 110°F
Kitchen Sink 1.5 GPM 110°F

[beautifulquote align=”full” cite=”CompactAppliance.com”]How much hot water do you need at one time? Do you need to run 2 showers at the same time or maybe a shower and a couple sinks? The chart [above] shows the range of water usage range and average water temperatures for various fixtures. We suggest using 2.5 gpm for a shower and 1.0 gpm for a bathroom as a reference point in determining your total simultaneous water needs.

For example, if you are running 2 showers at the same time, you will need 5 gallons of hot water per minute from the tankless water heater. If you were running a shower and the washing machine at the same time, you would need 4.5 gallons per minute from the water heater. In either of these situations, you will want to size the unit that meets or exceeds how much hot water you need at the same time.[/beautifulquote]

Propane vs Electric

Propane and electric heaters are the most common water heaters. However, there are many water heater options available and you should always take a peek and every possible option you have before finalizing a decision.

The biggest decision-making point is whether or not you’ll be using solar, standard electric hookup, or propane (or something else!). Each of these options is equal. None is better than the rest. It is all a matter of personal preference and tiny house accommodations at this point.

Propane is the common option for off-grid and solar tiny houses. Mainly due to the fact that it consumes less energy. As mentioned previously, you will need to invest in propane blankets to keep your system protected.

Electric is worthwhile if you plan to be hooked up year-round or are sure you will always have a parking location with a plug. This will eliminate the extra hassle of maintaining a propane tank and paying an electric bill.

Solar energy can be used to power an electric water heater, but you must have a system that can accommodate your unit. Most solar and off-grid tiny houses choose propane to conserve energy usage. If you have a solar system capable of powering the water heater then no need to worry.

Tank vs Tankless

[beautifulquote align=”center” cite=”Jenna from Tiny House Giant Journey”]Brittany Yunker owns a Tumbleweed Cypress with a six gallon RV tank electric water heater. This model retails at $270. In an effort to conserve energy, she switches her water heater on before showering and switches it off immediately after. It takes about twenty minutes to heat the water in the six gallon tank, therefore planning your hot water needs ahead of time is necessary with this method.[/beautifulquote]Since we’re talking about tiny houses this option should be pretty apparent which would save you more space. However, there are those that use both tank and tankless water heaters in their tiny houses, so let’s break down each a bit more.

Water heaters with a tank will, of course, “tank” up more space (har har!). It will use more energy because it will constantly heat the tank of water. You can counter this by installing a switch to turn the water heater on and off. Examples include turning it off when you sleep or only turning it on when you plan to use it (such before a shower or washing dishes). The only downside to the switch is having to wait for the water to heat up. This wait time will vary depending upon the size tank you have.

Jenna writes about tiny house owner Brittany’s electric tank water heater.

The tankless water heaters will resolve the previous issue of energy consumption by only heating water when it’s being used. This also saves you space because you won’t need to install a bulky tank. The biggest downside to tankless is cost. They tend to be on the more expensive side. A commonly suggested (and installed) tankless water heater is the Precision Temp RV-550 NSP. This unit retails at a whopping $1,175 as opposed to the previous $270.

Water Heater Overview

Tiny House Talk offers their “Top 5” list of ways to heat water for a tiny house. Be sure to check out their list and st

We’ve looked at the different components of water heaters and their pros and cons. What they can offer and which type of unit can suit your type of tiny house. If I failed to answer your burning question, ask below in the comments!

If you already live in a tiny house, I would love to hear about which water heater you chose and why.

As always, be sure to subscribe to the newsletter to get a first look at what’s coming out next. You can also drop me a line to make a suggestion for topics you’d like to read about in the future.



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Stephanie McQueen

Stephanie is the content curator and resource hoarder of all things tiny houses. She enjoys collecting information about tiny houses and writing easy-to-understand articles that help you make informed decisions whether you're building, buying, renting, selling, or parking your tiny house. Only thing she loves to do more than hoard information? Share it! Connect with Stephanie through LinkedIn, her portfolio, or her done-for-you marketing agency, Employed By Life Online.

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