Our Water Heater: Why we love it and how we almost killed it

There are many choices out there for tiny house appliances, and one of the most important (especially if you like hot showers) is your water heater. In a standard size home, you’ll usually find a gigantic water heater gargling and humming in the basement. In a tiny home, you have to think… well…. tinier. This might mean going tankless or purchasing a small tank water heater. For our tiny house, we went with a tankless propane water heater.

Our Tiny House Propane Water Heater

Our tiny house water heater is the PrecisionTemp RV-550 NSP. There are a couple of special features to this particular instant propane water heater that makes it the best choice for tiny homes.

propane water heater

PROS of the PercisionTemp Propane Water Heater:

  1. Water Temperature Rise. The PercisionTemp has an 88° F temperature rise per gallon per minute. That’s impressive and uncommon for such a tiny unit.
  2. Limitless, (Almost) Instant Hot Water. The PercisionTemp is capable of heating water within 10 seconds, limitlessly. Other instant units take up to 45 seconds to heat water.
  3. Compact. The PercisionTemp is a small 14″ cube. It fits easily under our kitchen counter.
  4. Floor Vent. As with all propane units, the PercisionTemp requires exterior ventilation, but this unit actually vents through the floor! That means you don’t need to cut a hole in the side of your Tiny House (which can be unattractive).
  5. Anti-Freezing Protection. The PercisionTemp will detect when it’s about to freeze and start up to protect itself. Keep in mind, freezing your unit is not covered under warranty. Read on for how we managed to screw this up.
  6. Needs almost no electricity. A small amount of electricity is required to ignite the unit. This is common with propane appliances. A 12-volt battery is sufficient. We can use this unit while running on solar, which was ideal for our situation.

CONS of the PercisionTemp Propane Water Heater:

  1. Expensive. The PercisionTemp retails at $1,150, making it one of the most expensive appliance choices for tiny homes.
  2. 10 Seconds to Heat Up. Even though 10 seconds is not a long time to heat water, a tank water heater would be absolutely instant (though limited by the tank size). When we shower, we like to take navy showers – meaning we turn the water off as we lather up. Every time we turn the water back on, we endure 10 seconds of cold water before the hot water kicks in. It’s not exactly a spa shower, but it’s efficient and eco-friendly.
  3. Need 0.5 gpm to work.  Extremely low-flow faucents (0.5 gpm or under) will not trigger the unit.

How we broke our water heater from a stupid mistake

This past winter we parked our Tiny House in the Colorado Rockies. Usually we kept the house warm, but from November to December we left the house unattended as we traveled to Europe. We didn’t winterize the Tiny House, because we were hoping our Envi heater could keep it from freezing while we were away. That was a mistake.

In late November, nightly temperatures dropped to below 0°F. Our Envi heater couldn’t keep up and the internal house temperature dropped to below freezing (32°F). Our water heater tried to trigger itself to ignite to prevent itself from freezing but failed. The trouble was, our propane tanks were freezing as well. At the time, we didn’t protect our tanks with heat blankets so their efficiency was significantly reduced. Our PercisionTemp was not recieving enough propane pressure to ignite, and eventually, the pipes inside the unit froze and burst. Water from our tank emptied through the water heater unto the ground beneath our trailer. Luckily, our house did not flood (thanks to the water heater’s floor venting).

propane water heater
The copper piping inside the unit burst from freezing

When we returned from our trip, Guillaume was able to fix our water heater by purchasing a few parts from PrecisionTemp and spending the afternoon as a DIY plumber. The total damage cost us $235 (plus shipping).

propane water heater

This mistake could have been prevented a number of ways:

  1. Occupants. Had we been around, the problem would have been noticed and rectified before the pipes froze.
  2. Winterizing the unit. We could have drained the unit and filled our plumbing with antifreeze.
  3. Propane blanket. Had we purchased a propane heat blanket before we left, the pressure would have been enough to keep the water heater from freezing. Our propane efficiency increases dramatically with the help of the blanket.

Propane Water Heater Tank Blanket

*Click here for more advice on Tiny House cold climate prep

Which water heater are you going to use in your Tiny House?

27 thoughts on “Our Water Heater: Why we love it and how we almost killed it”

    1. The tanks did not freeze, but they got so cold that my water heater did not receive enough propane pressure and was not able to turn on. The pipes inside my water heater froze, because the heater was not able to turn on and heat up, and the pipes burst. Make sense? So if the propane tanks are kept warm, they can give enough pressure to the heater so that it can turn itself on and prevent freezing.

  1. My husband is also a contractor and he doesn’t get the Tiny House thing either. He keeps repeating the same litany “If you want an RV, why not just *buy* an RV?” I think contractors just in the main don’t see the point, but that’s OK. There are all kinds of people with all kinds of tastes, and more importantly, all kinds of needs.

  2. Thank you for posting another informative article. My fiancee and I are building our tiny house in Durango, CO and we are just starting to put siding up, so I need to figure out which water heater we will be using (in case a side wall penetration is required). I have done some research on the Precision Temp RV-550 (and several others) and it looks like it could be a great option, but I have some concerns so I’m hoping that you can answer a few questions:

    1) I know you mentioned that you take navy showers, but I’m wondering if the heater is powerful enough to provide a hot shower with continuous operation? This unit is smaller than the others that I have looked at and seems like it might be a little under powered – the 88 degree temperature rise at 1 GPM translates to a 59 degree temperature rise at 1.5 GPM. If your incoming water is 42 degrees (a reasonable ground water temperature for the mountains in Colorado), then your hot water would only be 101 degrees, which is a little shy of the average shower temperature of 105 degrees (and that is assuming optimal operating conditions, which probably isn’t the case at high elevation).

    2) Other than the cold propane tanks not providing enough pressure, have you had any issues with your heater at elevation? What is the elevation where you have been using the water heater?

    3) Did you run into any issues with venting through your floor? RV floors are usually much thinner than tiny house floors (ours is about 6″ thick), so I’m curious about the installation details with a thicker floor.

    Thank you in advance for any information/advice you can provide!

  3. Great article as I am looking for hot water heater now! I was wondering if you have any articles on the propane plumbing or on your electrical that goes to all this. I am at the guts of my house and am looking for some deeper knowledge on these subjects. Thanks and rock on!


  4. Question for you from one tiny houser to another.
    I haven’t purchased my hot water tank yet but have been heating water as needed on propane stove. I left a space for one beneath my sink though.
    My question is how much use does your water heater get and how long does your propane tank last under that usage?
    Any advice for someone who is about to go from part time (summers)to full time year round on the road with their tiny?
    Loving your journey, perhaps one day we will meet on the road.

    1. Hi. I can’t really give you a number on the propane tank. It usually lasts comfortable over a month with showers and cooking. Our water heater gets the most use during showers and we take short showers.

  5. This for the GC. Their “Home” has all the systems that it needs. Just as not all houses need ALL systems . You build the home you want, and if you are the builder then you build what your client wants!! To the best of your ability. Different strokes for different folks.
    Sometimes you have to think outside of the box, and if that doesn’t work, build a different box. Good Luck to you and your partner.

  6. It’s worth noting that U.S. fuel efficiency regulations for water heaters, furnaces, and boilers appear to have mostly eliminated pilot lights in favor of electronic ignition. In my experience, this tends to increase the number of times the systems will fail and increases the likelihood of frozen pipes. Let’s just say I didn’t learn to solder pipes in shop class. :^)

    It’s also worth noting that the useful life of newer furnaces tends to be closer to ten years, where older furnaces often were good for a century. You get efficiency, but sometimes at the cost of reliability.

    So it’s all of us, not just those of us in tiny homes, that might do well to consider winterizing before long winter trips, especially if we’re in older homes that are not as well insulated as those from the past decade or so.

  7. Regarding your hot water heaters 10 second introduction to the Polar Bear Club; add a hot water re-circulation system to the shower plumbing. They have systems with auto temperature sensing, and can be turned on and off as needed. Instant hot water all the time for those Navy showers!

    at least you’re not rinsing with sea water . . . 😉

    1. Oh I’ve done the rinsing in sea water sailing from Hawaii to SoCal 😉 that’s a good tip, we’ve actually stayed in places where they have this system setup (much bigger places). The problem is that it would continuously use energy and we don’t need hot water all that often. I wonder which one is more efficient between the little extra energy use or the little extra water wasted…

      1. Switches can be added to stop/start the pump so the system isn’t in constantly circulation mode and heating water. In our country house, the shower is the farthest hot water usage from the HW tank. I flip a switch and when the green light comes on, we have hot water at the faucet.

  8. Isn’t it frustrating when you have to explain or defend your life to others?

    I’ve really enjoyed reading your traveling adventures and your knowledge of tiny homes. You both are an inspiration for the tiny home community.( It’s great your were able to fix your water heater fairly inexpensively.) Bless you both!

  9. Happy to hear you where able to fix it for parts. Amusing that you didn’t winterize before you left it in the CO winter. Given you have a home on wheels, I did find it curious you chose to park it there. There are places where winterizing isn’t needed. But I wouldn’t say that was one of them. 🙂

    1. Well, we love snowboarding so it was a conscious choice to park in the Colorado Mountains. We also wanted to test our house in winter conditions. As far as the heater failing, it was my own fault for disregarding propane pressure in cold environment. Had we had the heating blanket on the tanks, it wouldn’t have been an issue. We didn’t entirely winterize our house (such as draining water) because we were living in it through winter in Colorado.

  10. If you had simply bought an RV Trailer, you would not have any of the problems you have documented. Your “tiny house” is nothing more than an RV Trailer, if it was built per code and I suspect it is not. I have been a general contractor for 20+ years. I have built custom homes that cost less/square foot than 80% of the tiny homes supposedly taking the nation by storm – and these houses had a real foundation, electrical connections, sewer/septic systems, i.e. a Real House. Leave the “tiny house” playhouses for your kids and grandkids.

    1. It’s not because you don’t understand what we are doing and what we are getting out of it that you have to be condescending.
      Our water heater failed because our propane tanks weren’t heated. If we had bought an “RV trailer” the same exact thing would’ve happened since most of them have exposed tanks.
      Just as you’ve had much experience with building houses, we’ve met hundreds of RV owners that have had more issues than we’ve had with fewer miles and less use on their units.
      We also don’t want to live in a house that cost less per sqft. That “cost per square feet” metric is irrelevant when comparing a tiny house to other construction. Square footage is fairly cheap to add to a structure, you of all people, should know that. And when people go smaller, they can chose to have higher end materials. If you had 1,500sqft of hardwood floors to purchase, you probably won’t purchase the $6/sqft option. If you only had 120sqft to cover, you will be most likely to spend more and get better floors. But I’m probably not teaching you anything. We know our house cost quite a bit and we’re perfectly comfortable with that price tag. We wouldn’t want anything “cheaper.”
      Lastly, had we chosen an RV to do our trip, our story wouldn’t have been featured all over the world the way it’s been featured (just recently on MSN), we wouldn’t have the same traffic on our website and our YouTube channel (which generate income for us to live on the road), we wouldn’t be hosting workshops for other people to build their own tiny house (no matter what negative things other people tell them), we wouldn’t have been able to quit our 9-5 cubicle jobs to pursue travel journalism. Same thing had we chosen to indebt ourselves with an oversized house.
      Now think twice before claiming you might know everything about someone’s choices. It’s not because you don’t get it that you have the right to be condescending. You keep building “real houses” for whoever wants them and we’ll keep making tiny houses and other alternative housing options real homes.

      1. Masterpiece of an answer Jenna. Some just struggle to see the world through anything but their own limited vision. Well done to you and Guillaume for all that you have achieved through building and living tiny. A true inspiration! 🙂

      2. BAM! Great answer for the “general contractor”.
        You guys rock. Thanks for thinking outside the box and for being an inspiration.

      3. Now Now. People need to understand that your tiny house is your profession and income generator and not your preferred lifestyle. If that house were set in the back woods and didn’t move you wouldn’t last a year. As a poor kid in the 40’s, we lived in a single car garage; so, I know about small living and it sucks. Hauling buckets of water from the spring and using an outhouse in the winter is not an experience anyone voluntarily enters.
        Without someone else’s water pipe and dumping station life would get interesting. Washing clothes in a washtub, with a washboard, and hanging them on a line takes time and energy that’s how mom did it in the kitchen area and no one ate until she was done for the day because there was no room to cook.
        “Lastly, had we chosen an RV to do our trip, our story wouldn’t have been featured all over the world the way it’s been featured (just recently on MSN), we wouldn’t have the same traffic on our website and our YouTube channel (which generate income for us to live on the road), we wouldn’t be hosting workshops for other people to build their own tiny house (no matter what negative things other people tell them)”
        You keep selling but don’t get so upset when people are realistic.

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