For many homeowners, storage tank water heaters (and the bills that come with them) are an unquestioned part of home life. We all need hot water after all, and the convenience of a storage tank can come in handy.
As more and more people start to look at ways of using less energy around the home, however, tankless water heaters are becoming increasingly popular. If you’re concerned about the environment or making long-term savings – and no one says you can’t be concerned about both – they’re a great choice, using less energy than storage tank heaters because they only heat water when it’s needed.
If your storage tank heater is more than 10 years old and you’re thinking about a replacement (which you should be), it’s the perfect time to look at upgrading and going tankless. What’s more, their increasing popularity means greater choice at lower prices: there’s never been a better time to invest in a natural gas tankless water heater.
Below are some of the best models available on the market.
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What are natural gas tankless water heaters?
Tankless water heaters are more energy-efficient, and take up less space in the home, than storage tank water heaters. This is because storage tank heaters work by heating and then storing water in an insulated tank, which is then piped out to taps and appliances when necessary. This has the advantage of convenience, but has a real energy cost.
Because storage tank heaters keep the water in their tank at a constant high temperature, they’re remarkably energy-inefficient compared to tankless models, which only heat water as required. Large buildings and professional premises will likely not be able to give up their storage tank heaters just yet, due to the relatively large quantities of hot water required at once. But for most homeowners, a tankless water heater is a legitimate alternative that promises to significantly reduce heating bills.
There are three different types of tankless water heater – non-condensing, condensing, and hybrid – and any of them can be powered either electrically or using natural gas. If energy efficiency is your number one concern, and you live somewhere relatively small – a studio apartment, for example – then an electric tankless water heater may be the best choice for you.
For most homeowners, however, an electric tankless water heater will likely prove frustrating: they’re slower to heat water than natural gas heaters, which makes the lack of a hot water reservoir compared to a storage tank heater that much more evident. This is reflected in their lower flow capacity compared to natural gas tankless water heaters: if you’ll be drawing hot water at more than one point at a time, natural gas is the way to go.
Between the three types of tankless water heater available on the market, non-condensing heaters are the earliest model. As a result they may not be as efficient as the more recent designs, but they’re reliable and well-understood by most tradesmen. Non-condensing heaters use a single heat exchanger to raise the water temperature, and achieve an energy factor (EF) of 85% – a marked improvement on storage tank heaters, but notably less than condensing and hybrid models.
Non-condensing heaters are also less efficient on short draws of hot water; when washing your hands, for example. A further complication is that non-condensing heaters require the installation of stainless steel venting, an additional cost on top of what is already a significant purchase, and an even trickier installation job than would otherwise be the case.
Condensing water heaters are the second generation of tankless heaters, using two heat exchangers and reusing the heat from the unit’s exhaust to raise the energy factor to as much as 94% on some models (although, like non-condensing heaters, they struggle with efficiency over short bursts). An additional benefit of condensing heaters is that they can use regular PVC ventilation, making the job of setup a little easier than for non-condensing designs. However, non-condensing heaters are more expensive units to buy in the first place, so the decision between condensing and non-condensing may be a budgetary one as much as anything else.
The third generation of tankless water heaters is what is known as the hybrid heater. Pioneered in the USA, these contain a small hot water reservoir which increases the heater’s efficiency for small draws of water, raising the overall EF on some hybrid models to 96%. They’re also quicker to heat up in the first place, and like condensing heaters work fine with regular PVC ventilation.
As you might expect, however, the newest tech in a marketplace is always the most expensive; and the relative newness of some hybrid models means they’re more likely to have unforeseen issues, and that professionals are less likely to have a quick fix when they do.
Compared to storage tank heaters, all natural gas tankless water heaters are a serious step up in terms of efficiency, so it’s worth thinking about your budget and how your home uses hot water before deciding which type will be best for you.
Why buy a natural gas tankless water heater?
There are a number of good reasons:
- Energy-efficiency. Switching from a storage tank heater to a good condensing or hybrid natural gas tankless heater could see a saving of as much as 60% on your water heating, or between $200-400 a year. Given the average 30-year lifespan of most tankless heaters, you can count on yours paying for itself long before you’re done using it.
- Smaller footprint. This is true for your environmental footprint: because tankless heaters only run when you need them to, you’re using less energy, which is good for the environment and your wallet. Tankless water heaters also have a small footprint inside your home, taking up much less space than the hulking storage tanks which dominate and even completely fill smaller rooms.
- Heat on demand. As long as you’ve done your homework and bought something with sufficient flow capacity (measured in gallons per minute, or GPM) for your home, there’s no need to worry about running out of hot water.
- Longevity. Tankless water heaters last considerably longer than most storage tank models. While storage tank heaters will need to be replaced every 10-15 years on average, most tankless heaters will last at least twice as long as that. Natural gas tankless water heaters aren’t only an investment for the long term, they’re a time-saver and a stress-reducer too.
- Go for the upgrade. If it’s about time you replaced your storage tank, it’s worth considering going for the upgrade. A natural gas tankless water heater will cost you more than a storage tank heater, but over its lifespan will more than pay for itself in terms of energy savings.
- Increase your value. As energy-efficiency becomes an increasingly high-profile issue, the value of fitted energy-efficient appliances like tankless water heaters continues to rise. It’s worth talking to estate agents in your area to get their opinion, but when you consider the energy savings of a tankless heater and the costs involved in getting one properly set up, there’s every reason to make yours a selling point for your property.
- Go natural. Among tankless water heaters, natural gas wins over electric in almost every situation. If you live in a small studio apartment and want to squeeze every drop of energy efficiency you can out of your water heater, an electric tankless heater might be the way to go. But if you live anywhere larger, natural gas will give you serious energy savings without the frustration of waiting around for your water to get hot.
Things to consider
If you’ve decided to go for the upgrade, there are a few things to consider:
- Size. How big is the heater? Size will have an impact on capacity, but remember these aren’t storage tank heaters, so bigger doesn’t necessarily mean better. In fact, one of the selling points of tankless heaters is that they have a much smaller footprint than storage tank models. Think about where you want to store your heater, and look for something that’s a good size to fit.
- Flow rate. Measured in gallons per minute (GPM), this reflects how many gallons of water a heater can heat per minute. A good rule of thumb for homes is that 4-5 GPM is sufficient flow capacity for a single-bathroom house – if you have more than one bathroom, look for a heater with a GPM of 6 or more.
- Energy factor (EF). This is a simple measurement of how efficient the heater is. Or, more scientifically, how much of the energy it consumes is transferred to the water as heat. A decent non-condensing tankless heater should have an EF in the mid-to-high eighties, while condensing and hybrid heaters should have an EF well over 90%.
- Price. Expect to pay upwards of $500 for a non-condensing natural gas tankless water heater, with condensing models costing about twice as much and hybrid heaters even more. When it comes to natural gas tankless water heaters, the total cost almost certainly isn’t limited to the price you pay for the unit itself. Unless you’re a professional yourself, you’ll need expert help installing the heater. Among other tasks, you’ll need to run a gas line and a dedicated power line to the unit, as well as installing ventilation and possibly additional piping. Don’t let this put you off buying one: the increased efficiency of a tankless heater will generate real savings when it’s time to pay your heating bill.
- Warranty. Natural gas tankless water heaters are supposed to last at least 20 years, and preferably 30 or more. If you’re going to invest your hard-earned cash in one, go with a manufacturer that’s got enough confidence in its heaters to sell them with a long-term warranty.
- Your needs. As with any serious consumer purchase, it’s worth taking the time to think about your particular needs before starting to compare different models. How many points will you be drawing hot water from? How many will be in use simultaneously? How many people live in your home? What’s its maximum capacity? How many bathrooms do you have? These are some of the questions you can ask, but you know your own needs better than anyone: think about them and you’re bound to be happier with your purchase than you otherwise would have been.
Risks and warnings
- Installing a natural gas tankless water heater is a difficult and potentially dangerous job which should be done by professionals. If you’re a professional yourself, you can save some money by going DIY, but otherwise it’s worth paying a little more to get the job done well. Installing a tankless heater involves running gas and electric lines to the unit at the very least, so it’s not something to be taken lightly.
- To preserve the long lifespan of your heater, you should flush it every once in a while. If you live in a hard water area, once a year is ideal; otherwise, you can get away with once every 2-3 years.
- Have your tankless water heater inspected regularly, to keep it safe and make sure you can keep enjoying its energy savings for many years to come. When it’s first installed, make sure to have it thoroughly inspected before switching it on: key problem areas to look out for include the igniter, fan, exhaust and electrics.
- Be aware that the outflow pipes on a natural gas tankless water heater will get hot, so be sure to install it somewhere out of the way of curious children and animals. If you have children and they’re old enough, you can also educate them about the risks and dangers involved with the heater.