Microwave boiler launches as retrofittable alternative to heat pumps and gas

Posted: April 11, 2021 by oldbrew in Emissions, Energy
Tags: , ,

Domestic gas central heating boiler

The battle to sell replacements for gas boilers, likely to be unavailable new in the relatively near future (2030?) in the UK, is on. As this microwave option appears we ask what, if anything, is wrong with existing electric boilers? Needless to say, anything electric can’t be more ‘low carbon’ than its electricity source, which is usually 40-60% gas in the UK. But using electricity for heating water instead of making hydrogen has some logic to it.
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A new heating technology has emerged from under the radar as a potential alternative to both heat pumps and gas boilers in the quest for low carbon heating, reports H&V News.

Heat Wayv, a UK energy technology company, has unveiled the world’s first microwave boiler intended as a zero-emissions replacement for gas boilers, with a view to the phase-out of natural gas in new-build homes from 2025.

The company originally developed the microwave technology as a portable cooking device for military use and has now applied it to the heating of water.

Co-founder Phil Stevens said: “The end of the [natural] gas boiler is inevitable and scheduled. But the proposed replacement technologies do not work for consumers as they are either too expensive to install or too expensive to run. We looked for a clean technology where the boiler would cost the consumer the same to buy, same to install and same to run as a gas boiler.”

Mr Stevens and co-founder Paul Atherton believe that it can provide a lower-cost and simpler alternative to heat pumps for use in new-build homes, while at the same time being straightforward to fit in existing homes.

This they believe gives the technology a dual advantage over gas boilers – its lack of carbon monoxide emissions and electric power make it a compelling option for boiler replacement now, while ultimately it offers a more practical and lower cost alternative to the hydrogen grid, currently being proposed.

Mr Atherton said: “We believe this technology offers a more practical solution than hydrogen, with considerably less investment than the billions hydrogen will cost, but even if the hydrogen grid does become a reality, for the next 30 years or however long it takes this is a perfect bridging technology.”

The company is in advanced talks with housebuilders to trial the technology in a real-world setting next year, and then to optimise it with a plan to sell the boilers through wholesalers in 2024.

The concept brings with it a host of claimed benefits beyond its plug and play installation: it is 96% efficient; it is silent in operation; installers can be trained on a half-day course and as it is largely based on solid-state components, it is low in maintenance, so will be offered with a ten-year warranty.

Continued here.

  1. How can a microwave heater be much more efficient than any other electric heater?

  2. tallbloke says:

    Kevin, by cutting out the convection requirement and thermal losses through time lags and inefficient usage.

  3. Stuart Brown says:

    TB, the article says it has a tank in it. I’m with Kevin – I can’t see how this is better than a tank with an immersion heater in it. If it’s meant to provide hot water on demand, the best electric showers are just under 11kW, equivalent to 45A, and requiring something unusually large in the wiring department – so needing a certified electrician at least. They are also quite a bit smaller, simpler (and I’d suggest cheaper) than this thing. Indeed they say the initial version of the boiler is 10.5kW. Go beyond 60A and you are probably digging up the street to upgrade the cables for a lot of houses.

    On the other hand my gas boiler is capable of putting out 38kW, no tank, is over 90% efficient (OK, can be under certain circumstances) and runs on a fuel that costs under fifth of the price of electricity. It can be converted to run on LPG. Hmm. Looks like LPG is still considerably cheaper than electricity per kWh, as long as it remains legal.

    “We believe the gas boiler’s ship has sailed.”

    Yeah, right, only because of deranged government policy. This things ship needs holing below the water-line before launch IMHO.

  4. oldbrew says:

    Microwave boiler is ‘96% efficient’.

    New natural gas boilers are rated 94–95% efficient here…
    – – –
    Note: in the post intro, ‘using electricity for heating water’ means the water for the CH radiators as well as for taps, immersions etc.

    Can heat pumps compete with electric CH?

  5. JB says:

    “5 kW to 60 kW”

    “also connected so that the devices can work intelligently with the grid”

    Like Stuart pointed out, major problems there. This would go over really great in Texas after their recent freeze over. Next thing we know, somebody will want to use the same or similar for heating the house. My first house was a Boise-Cascade factory built unit. I took the standard electric heat package as it was so cheap–for a back up (ceiling embedded coils). But the bills were not Our power usage nearly trebled (~1.5MWH/mo) the first winter, the feet were always cold. This went away as soon as I installed hydronic heating using a modified NG water heater, assisted by a water heating wood/coal burning stove I built. Getting off forced air was a boon to the family’s respiratory needs.And we were warm and comfortable for the first time.

    All electric homes were a big sell when I was a kid. Then it suddenly evaporated. Never found an affordable electric stove yet that wasn’t a bane for cooking and ruining pans. The recovery time of electric element WH sucks. Life was never so good than when we got off those two.

    My present house service panel is rated for 100A. Its loaded with A/C 30A, Dryer 30A, RV-Shop 50A, and at least 16 20A breakers for furnace and incidentals. NO electric stove. This thing is maxed out, and I could easily over load the main on a hot summer day. If I had to add a stove and electric WH I would be spending $2K to run a new service line from the pole, a new service panel, and a nightmare of retrofitting the wiring going into it.

    And then for what? To have cold water/house on a windless, cloudy day? Load manage the house so I could use the shop?

  6. tallbloke says:

    For sure gas is cheaper. The question is how long we’ll be allowed to use it. I run my car on LPG at 53p/litre. Domestic use LPG is cheaper still, around half that I think. Problem is getting permission for a big tank in a suburban garden.

  7. Gamecock says:

    How many amps does it take to run it? Residential electrical systems are not sized with a lot of free board. Changing energy source from gas to electric may require changes to household electrical systems.*

    One can’t help but sense the irony of Britain moving to electrify everything as they move to destroy their electrical supply.

    *Be sure to add capacity for charging your electric car, too.

  8. tallbloke says:

  9. stpaulchuck says:

    where’s all this magic electricity supposed to come from?? windmills and solar panels? We’ve seen that movie. It doesn’t end well for the users.

    more endless twaddle about magic electric this or that which will stop global heating which has nothing to do with a trace gas.

  10. tallbloke says:

  11. Curious George says:

    Why would microwave at 96% efficiency be any better than a resistive heating element at 100%?

  12. I’ve had a look at the FAQ on their site. There is a load of technobabble, but they seem to be claiming that a conventional immersion heater is only 75% efficient during the high energy consuming heating phase. Given that an immersion heater is, by definition, immersed in the water that it is heating, where else can that missing 25% possibly be going?

  13. Daedalus says:

    96% efficient! So 1k of electric in and 0.96kW out. A good heat pump will transfer 3kW for each 1kW of input, or if you like is 300% efficient. This thing is dead before it starts.

  14. A C Osborn says:

    I don’t know why you are all knocking it so much, if it doesn’t do what they say it does it will soon be found out in testing.
    I have always found microwaves very fast for heating water because it is acting directly on exciting the molecules and not dependent on convection within the fluid.
    Of course to be really competitive the Electriciy Industry would need a massive shake up with a lot of Nuclear power. Currently there is no way to generate enough electricity to replace gas.

  15. oldbrew says:

    This article is more specific about what the boiler offers, e.g.:

    The electricity load will be about the same as an electric oven, the makers say. They say the boiler is 84% efficient in converting electricity into hot water, and another 12% of waste heat is recycled, giving a total efficiency of 96%.
    . . .
    “…the boiler will cost the consumer the same to buy and install as a gas boiler.”


    A lot lower cost than a heat pump at least, and works with existing CH pipes, radiators etc.

  16. Gamecock says:

    ‘I don’t know why you are all knocking it so much, if it doesn’t do what they say it does it will soon be found out in testing.’

    Because this article has nothing to do with heating water. The purpose is to tell us that Net Zero will work. It is propaganda. For now. Whether it works out isn’t relevant.

    We get monthly articles on technology breakthroughs – all of which are sketchy. They can’t handle the simplest critical review. “It will soon be found out in testing.” Note that the articles could – should – be published AFTER testing. The Lefty press publishes what fits their agenda. It suits their purpose to publish BEFORE testing.

  17. The Guardian article says that the makers say that the electricity load will be about the same as an electric oven, 3kW to provide heat and hot water for a whole house???

  18. Old Brew, Kevin W does not the article printed in the Guardian tell that it is political and likely not to have technical basis? A journal or newspaper that promotes things such as climate alarmism, BLM, white supremacy, gender issues etc is not worth looking at and definitely not worth quoting.

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