How much electricity does MVHR use a year?

A unit drawing 40 watts continuously uses about 350 kilowatt hours a year. At the mid-2026 price cap of about 26 pence per kilowatt hour that is roughly £91 a year. Lower fan power means lower use.

Does this calculator include heating savings?

No. It covers only the electricity to run the fans. The heat recovery reduces heating demand separately, and that saving depends on how airtight your home is, so it is not included here.

Why does MVHR run continuously?

MVHR is designed to ventilate the whole home all the time at a low background rate, boosting when needed. Turning it off would leave the home under-ventilated, so the running cost is based on continuous operation.

Calculator

MVHR running cost calculator

This calculator estimates what an MVHR system costs to run in electricity over a year. Enter the continuous fan power of the unit and your electricity price, and it returns the annual electricity use and the yearly running cost, assuming the system runs continuously as MVHR is designed to.

By VentRight Editorial · Last updated 2026-07-08 · Impartial · Sourced

How is the MVHR running cost calculated?

The calculator assumes the unit runs continuously, which is how MVHR is designed to work. It multiplies the fan power by the hours in a year, 8,760, to get the electricity used, then multiplies by your electricity price. It covers the electricity to run the fans, not the value of the heat recovered, which depends on your home.

The result is an estimate for steady continuous running. Short boost periods, when extraction increases, add a little on top, and a system with high resistance ducting will draw more power than the unit rated figure. For a precise number, use the actual measured power of your commissioned system.

What fan power and electricity price should I enter?

For fan power, use the continuous power of your unit from its datasheet, often around 30 to 90 watts, with 40 watts a reasonable default for a well designed system. For price, use your own electricity unit rate in pence per kilowatt hour. The default is about 26 pence, the mid-2026 price cap average, but your tariff may differ.

If you do not know the unit power yet, the default gives a representative figure for a typical domestic system. Swapping in the real datasheet power and your own tariff makes the estimate specific to your situation.

Sources: Ofgem

Questions

How much electricity does MVHR use a year?: A unit drawing 40 watts continuously uses about 350 kilowatt hours a year. At the mid-2026 price cap of about 26 pence per kilowatt hour that is roughly £91 a year. Lower fan power means lower use.
Does this calculator include heating savings?: No. It covers only the electricity to run the fans. The heat recovery reduces heating demand separately, and that saving depends on how airtight your home is, so it is not included here.
Why does MVHR run continuously?: MVHR is designed to ventilate the whole home all the time at a low background rate, boosting when needed. Turning it off would leave the home under-ventilated, so the running cost is based on continuous operation.

Tool · v1

MVHR annual running cost

Annual electricity use and cost for a continuously running MVHR unit, from its fan power and your electricity price.

With the default inputs (Continuous fan power = 40 W, Electricity price = 26 p/kWh) the Electricity used a year is 350.4 kWh; Running cost a year is 91.1 pounds.

Result

Electricity used a year: 350.4kWh
Running cost a year: 91.1pounds

How this works

This calculator assumes the MVHR runs continuously, 8,760 hours a year. It multiplies the continuous fan power in watts by the hours in a year to get the annual electricity use in kilowatt hours, then multiplies by your electricity price. The default price of 26 pence per kilowatt hour is the Ofgem price cap average for the third quarter of 2026, including VAT. It does not include the value of the heat recovered, which depends on your home.

Each result is computed on the server from the inputs above using a versioned formula stored in the database. This version (v1) has passed its 7-day test window and is the currently-live version. Nothing is calculated in your browser.