Is the Flow boiler worth it?

UPDATE: The Feed-In Tariff is now closed for new applications. To find out about the new scheme designed to replace it, click here.

Earlier this year a new domestic boiler was introduced onto the market that produces hot water as well as electricity that can be used in the home to power lights and appliances.

The Flow boiler is a type of CHP boiler – where CHP stands for combined heat and power. Up to now, CHP boilers have been used to great effect in commercial heating situations as well as multi-dwelling properties but this is the first time a company have tried to crack the domestic CHP market aside from a very brief foray into the market by Baxi in 2011.

Here we want to put Flow’s CHP offering under the spotlight, however we want to make it quite clear before we start, we haven’t installed one of these boilers in our homes, this is purely based on the figures available on their website and general trends in the CHP market.

The Flow CHP Boiler offers

So the Flow has two offerings – the first is the Flow Freedom offer

Flow Freedom involves paying £3,675 upfront for your new boiler (inclusive of VAT). You need to pay installation on top of this and the figure they state on their site is £1,800 but obviously this varies from house to house. Obviously if there is a lot of pipework to change then this number could escalate very quickly, but likewise if it is a relatively simple install then the install price could be lower.

Under this offer, you are required to sign up to Flow’s energy tariff, which is actually very competitively priced (e.g. 10/11 p/kWh of electricity and 3/3.5p/kWh of gas depending where in the country you are).

You are required to pay for all the gas you use (as you might expect!) but also all the electricity – you can’t use the free electricity you produce – or at least you can but you have to pay for it!

You are also required to sign over your Feed-in tariff payments to Flow for the 5 years of the offer.

In return, flow will give you a payment each month of £80 – so a total of £4,800 over the 5 years.

After the 5 years, you then can benefit from the FIT which get reassigned to you – this means you get paid 13.24p for every unit (kWh) of electricity you produce.

Getting a Flow Boiler without any upfront payments

The second offer is Flow Finance.

Like the name infers, this allows you to get the boiler on finance so there are no upfront costs. The finance costs £75.50 per month for 5 years – so the total payment is £4529.89 – this however does not include the cost of install, which in some cases can be added to the loan too.

Aside from that – the offer is the same as Flow Freedom, you need to take their energy tariff, you need to pay for all gas and electricity you use in the home and you need to assign the FIT over to Flow.

In return you will receive £80 reductions on your home energy bill every month for 5 years – totalling £4,800.

Do the numbers stack up?

Lets compare the Flow Freedom offer with a normal boiler install – we have picked a £900 Worcester Greenstar heat only boiler from Plumbnation (Inc VAT).

Install wise we have spoken to a variety of our partners and have come out at an install price of £900 (inclusive of VAT) including the installer margin. We have had one installer who will put this on the wall for just £600 though!

Therefore for this normal boiler install we are looking at a price of £1,800 inclusive of VAT.

Under the Flow Freedom offer, the cost of the boiler + install (based on their estimated prices) would be £5,475 inclusive of VAT so about £3,675 more.

For a regular boiler though you need to pay for all the gas you use and you wouldn’t get any rebate from the installer unless they were feeling particularly generous.

Under Flows offer you would get back £4,800 over the 5 years so the final cost to you would be £5,475 less that – so just £675.

On these numbers alone, it certainly stacks up – especially when you take into account the Feed in tariff payments that would be due after the 5 year ‘contract’ with Flow was up. However there is obviously the cash you need to find upfront!

How much could the remaining FIT be worth to a household?

This question is a little bit like how long is a piece of string to be honest, because it entirely depends on the amount of electricity produced by the system.

The boiler when it is running will generate 1kW of power, so if you generate a unit of electricity with it you are going to get paid 13.24 pence regardless of what happens with that electricity.

If you use the electricity in your home then you make a saving of about the same for each unit produced (10-15p / kWh) since you don’t need to buy it from the grid.

You could export the electricity at 4.77p/kWh, but obviously the energy saving is far better!

If the boiler was on for 1500 hours per year (1200 hours during the winter months for heating and remainder just for hot water) then you would get paid just shy of £200 each year for the remaining 15 years of the tariff (remember Flow take the first 5 years worth of tariff)

This doesn’t take into account the energy savings if you manage to use the electricity – which could take the savings to £400 a year.

So again the numbers work here!

So what is the downside of the Flow boiler?

Firstly the current Flow boiler is an 18kW-condensing boiler that will heat a 3-5 bedroom house depending on heat demand. It also currently requires a separate hot water tank (like a heat only boiler), therefore if you live in a small house where space is a premium it may not be for you. Likewise if you have a combi boiler already, then you will need to install a new hot water tank, which might be an inconvenience. Flow are working on both a combi version (without hot water tank) as well as larger units to heat bigger properties.

The major flaw with CHP heating is that you can only produce electricity while the boiler is producing hot water so in domestic settings when the boiler is only on for an hour or so during the summer months to produce hot water for washing, the amount of electricity that will be produced is actually very small. Likewise there is no battery storage element to the flow so unless your boiler is on when you want to use the electricity it is likely going to get exported. However since you can program the boiler when to turn on the hot water and heating, it shouldn’t be difficult to set this at a time when you are home in the evening.

Another issue is that since the Flow boilers are doubling as electricity generators, they will consume slightly more gas than a modern boiler when they are operating, and will increase the annual gas bill by about £40.

The final issue and perhaps the most serious one is that CHP is a relatively unknown technology. Despite the fact the boiler was in development for over 10 years, the flow boiler only comes with a 2 year manufacturer’s warranty (although if you stay with flow energy this will be extended to 10 years).

This for us is the biggest issue, one can very easily go and buy a new boiler with a 7 year + warranty – so why take the risk! Why haven’t any of the boiler big boys (e.g. Vailliant, Worcester Bosch) taken the jump into domestic CHP – their lack of activity could in fact be the most telling!

UPDATE: The Feed-In Tariff is now closed for new applications. To find out about the new scheme designed to replace it, click here.

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