Can a Tankless Water Heater be Installed Outside?

Tankless water heaters solve all sorts of problems for homeowners and landlords alike. They can be less expensive than traditional tank water heaters and they take up less space because they don’t store water.

They have the added benefit of being able to cope with having to produce a lot of hot water within peak times without running the risk of running out of hot water too.

Can a Tankless Water Heater be Installed Outside?

They are a brilliant modern invention that makes having a constant supply of hot water all over your house something to be taken for granted.

Kids of today probably won’t ever remember standing in a shower with suds all over them, when the stream of hot water suddenly turns to freezing cold within a split second as the last of the hot water runs out.

Yes, tankless water heaters have solved a lot of the issues that immersion heaters are known for, but they are not all created equal, we have found.

Some immersion heaters, while being positively compact compared to their tank counterparts, are not exactly considered tabletop appliances and they still take up a significant amount of space within the home.

Because of this, some manufacturers now produce tankless water heater units that can be attached to the walls in a variety of angles to make them more space-efficient in different settings, and some are even able to be installed outside, on an external wall of the house.

There are a few key benefits to investing in a water heater that can be mounted outdoors, and there are some cons too, so let’s take a look at some of the ways that tankless water can have an effect on our homes.

Tankless Water Heaters: A Brief History

Although we think of electric tankless heaters as a modern domestic solution, they were actually invented way back in the nineteen-twenties.

Unfortunately, they didn’t take off at the time because the gas-powered heaters were superior and more efficient then. Until the 1970s, tankless water heaters weren’t considered good enough to be of any use in a domestic situation.

As the efficiency of the technology refined, they became more viable. Also, a steep increase in property prices in the western world over the last fifty years has led to space-efficient appliance designs being more and more popular as space is at such a high premium.

Environmental awareness also means that people are more likely to choose cleaner energy options for their utilities wherever possible and while not all electric energy is created in a green way yet, there is no such thing as eco-friendly gas.

The future is likely to see more electrically powered necessities in the near future and a decreased reliance on finite and harmful fossil fuels, so electric water heating was a natural step in that direction.

While there are still tank immersion and hybrid heaters widely available, they are no longer notably more popular than their tankless rivals.

Pros and Cons of Tankless Water Heaters

There are swings and roundabouts with any innovation in technology and the same could be said for tankless water heaters. Here are some of the key benefits and drawbacks to their use over gas-powered tank heaters.


  • Energy-efficient – Tank water heaters waste considerable energy in heating and reheating water stored in the tank just in case it is needed, whereas electric tankless heaters only heat the water that is used as it is required.
  • Lower utility costs – Because tankless heaters are more energy-efficient, they can lower the cost of your utilities by switching to one.
  • Time-saving – tank heaters would need a minimum of an hour to make a fresh tank of cold water into hot water. Then, once that is gone, it’ll need more time to heat up the new batch.
  • Longer-lasting – We’ve heard many people say that the quality of gas tank water heaters has decreased in recent years and they find that one they bought in the 60s lasted them for thirty years, while modern ones only last for ten. We can’t tell definitively whether this is true, but we do happen to know that quality tankless water heaters are expected to last for around twenty years, while the life expectancy of gas tank heaters is around a decade.
  • It doesn’t run out – Unlike the water supply in tank water heaters, the tankless heaters won’t run out of hot water, because they don’t store it, it runs through them. Tank heaters heat up a set quantity of water and then when some has gone, they replace it and reheat the tank. If you have a large tank then you shouldn’t run out of hot water, but it will take more energy to heat up larger amounts of water, whereas a tankless heater only heats the water you use and never runs out. As long as there is a water source coming into the heater, there will be hot water.


  • Inconsistent temperaturesInconsistent water temperatures are one of the main buyer complaints about tankless water heaters. When hot water is in high demand such as during the evenings when more people are home, some water heaters find it hard to divert enough resources to keep multiple taps supplying steaming hot water at the same time.

    Splitting the machines’ focus can create cold spots in the flow of water or make the flow of water only warm instead of hot. Some users complain that water varied in temperature when too many water outlets are running at once, but they are usually able to cope with a shower and a tap running simultaneously.
  • Gas versions are available – while this might be a pro in your eyes, switching to renewable energy wherever you can is the best thing for everybody. There may be gas tankless heaters available, but you should think seriously about the environmental impact of buying one before you commit to the sale.
Can a Tankless Water Heater be Installed Outside?

Can Tankless Water Heaters Be Installed Outside?

The answer to this question depends completely on whether the type of tankless heater you opt for is designed for use outside.

Even if you do have a heater that can be installed on an external wall there are a few other considerations to figure out before you can start enjoying the effects of your new water heater.

Do They Have A Power Source?

Most tankless heaters whether electric or gas-powered will need some kind of electric power source to run the machine. Gas ones will also need a gas supply, so you’ll need to choose a wall where this won’t be a problem.

Will It Have Shelter?

Electric tankless water heaters generally need some form of shelter against the elements to fully protect them. Gas ones generally do not.

Is it Going To Be Placed Near Doors Or Windows?

Indoor tankless water heaters require ventilation so the harmful fumes aren’t released into the house.

Outdoor varieties do not need ventilation since they are already outdoors, but they should not be placed close to vents, doors, or windows that could be opened. This is because you would risk carbon monoxide gases coming into your home.

Do You Experience Freezing Temperatures?

If you live somewhere that is sometimes exposed to sub-zero temperatures then you might want to consider insulating the pipes around the unit.

While the units themselves are able to withstand the elements including cold temperatures, the pipes are the most susceptible to being damaged by cold weather.

Is it Going To Ruin Anyone’s View?

With all these factors to consider, it’s no wonder that you could find yourself with only one or two suitable sites for your outdoor water heater to go.

Wherever you decide to mount it, just remember that they aren’t everyone’s idea of a picturesque view so make sure they aren’t going to be spoiling your or your neighbors view from any windows. It’s always nice to be neighborly, after all.

Final Thoughts

Many people find that tankless water heaters are an energy-efficient and space-saving solution for heating household water. Unlike the traditional tank heaters, they don’t waste resources through standby loss as they only heat what you use.

Choosing to install your water heater on the outside of your home has a few key benefits. The first of these is that you could lower the risk of carbon monoxide leaks from faulty ventilation in your home.

Any poisonous fumes are already outside when they leave the machine, so there’s no need for extensive ventilation systems winding through your house.

Another key benefit is that it will not take up space in your home where they can be unsightly to look at.

Given all these benefits it’s no wonder many people choose to have their heaters installed outside.

You just need to ensure you have considered all of the factors on our list to find the right place on your house to put the heater and work with a qualified installation expert to do the work safely.

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