The FHT Stove
A stove for a carbon neutral world
Net Zero CO2
“UK to have Net Zero
  CO2 Emissions by 2050”

UK Government announcement July 2019
This will require:
  • Arrow
    Huge programme of home insulation and low energy new builds to reduce heat demand
  • Arrow
    Low temperature heat pump systems replacing gas and oil boilers, or..
  • Arrow
    More expensive renewable fuel substitutes for current gas and oil
Energy Label
Wood burning stoves can be an important part of renewable fuel heating systems of the future, particularly contributing heat on the coldest days when power networks are stretched and heat pumps are at their lowest efficiency. A wood burning stove also gives some security in a more volatile world with less predictable weather patterns and potentially less reliable electricity networks. However, to fit in this new world, wood burning stoves need to be:
FHT Stove
  • Tick
    Lower heat output to correspond to better insulation
  • Tick
    Highly controllable heat output to maintain customer comfort
  • Tick
    Seamlessly integrated with low-temperature renewable heating systems
  • Tick
    High efficiency and low emissions
  • Tick
    Designed to burn quality, renewable, wood logs
The FHT Stove achieves all these objectives and more!

Read on for more details...
In June 2019, the UK Government announced that, “The UK will have net zero carbon dioxide emissions by 2050”. Irrespective of the debate concerning the exact meaning of ‘net zero’ this important announcement is likely to be the first of many similar or more challenging announcements around the world in the race to reduce CO2 emissions to limit global warming.

The reality of such announcements is not only that the use of fossil fuels will need to rapidly reduce over the coming decades, but that the amount of energy used in all areas of life will have to rapidly reduce - for homes this means a huge programme of insulating existing homes and building low energy new homes and may require many to convert to electrically powered heat pump heating systems. Alternatively, renewable fuel replacements for gas and oil, such as renewably generated hydrogen and bio-oil, may be available but at higher costs such that better insulation will be required to reduce the costs of heating.

Wood burning can make a strong contribution to the ‘greening’ of our homes, providing genuinely renewable, low carbon heat during periods of peak demand. With well insulated homes, this could make wood burning a far more significant contributor to the total energy used for space heating and water heating in the future, whilst not increasing wood consumption beyond sustainable, localised production.

With increasingly unpredictable weather patterns, combined with a far higher reliance on electricity to distribute energy, having a wood burning stove that is suitable for well insulated properties may also be a comfort as a ‘backup’ to cope with unreliable power and extremes of weather.

The best stoves provide efficient and clean burning of quality wood, but to attain the best performance the output range may be limited to ensure clean burning - some stoves already have restricted controls to achieve the current DEFRA Smoke Exemption conditions for example. Burning coal is unlikely to be possible in the future and does not satisfy the requirements for renewable heat, so the FHT Stove is designed to burn wood logs only.

The FHT Stove is ideally placed for the emerging low carbon future! Based on a small (5kW nominal) convector stove, the ability to disperse heat to other rooms and/or hot water when not required in the area around the stove is absolutely unique.

The benefits are numerous, and are summarised as follows:
  • Instantaneous ‘switchable’ heat transfer dramatically increases the output range of the stove and allows...
    • maintenance of comfort conditions around the stove (no overheating)
    • pleasant radiative heat to the room with excess convective heat transferred
    • effective use of the excess heat in other rooms or for hot water
  • The wide range of heat control around the stove enables...
    • stove to be lit comfortably for more days of the year, so increasing ‘green’ heat
    • stove room output as low as 2kW and up to 6kW without effecting efficiency or emissions
  • The unique FHT Stove design does not change the firebox burning conditions, so...
    • clean burn conditions and maximum efficiency are maintained at all times
    • existing, high efficiency, low emission fireboxes can be ‘FHT enabled’ with a few extra components
  • Ideal match to new and renewable heating systems, particularly...
    • air-source heat pumps (ASHP)
    • most likely to be used when ASHP performance is poorest
    • works with low temperature and underfloor heating systems
    • no restrictions on circuit type or layout
    • displaces peak winter electricity demand - Demand-Side Management measure
    • fail-safe design ensures the stove can operate safely in volatile network conditions
    • requires very little electrical power to operate where battery ‘standby’ systems may be more common in the future
How does the FHT Stove fit future home heating requirements?

A UK 3-bedroom, semi-detached home with moderate insulation measures (wall and loft insulation, double glazed) will typically consume between 12,000kWh and 15,000kWh of gas for heating (depending on age) and may also consume a further 1,500kWh ∼ 3,000kWh pa for hot water heating (depending on number of inhabitants). With further insulation measures the space heating requirement may reduce to 8,000kWh pa with economically valid measures - further savings may be achieved but may not be economically or aesthetically viable.

For a typical UK location, this level of space and water heating suggests that between 3 and 8 kW of heat will be required to heat the home and for water during the coldest days1. More will be required for larger homes and in northern areas and less for smaller homes and in southern areas. This suggests that a stove able to modulate room output between 2kW and 6kW may be ideal. Larger outputs without the ability to be modulated whilst achieving low emissions will lead to overheating and waste of valuable renewable heat, or more likely will put the user off lighting the stove.

A firebox able to modulate on air controls between 4kW and 6kW (nominal 5kW) with the FHT Stove components will be able to match the required heat range, exporting excess heat when required to other rooms and to heat the household hot water. Comfort conditions can be maintained in the room with the stove whilst providing the cheerful and pleasant radiative heat required to overcome the winter blues!

1 Heating requirements based on 2,000 degree days pa and heat requirement for 16 DD (-0.5°C average daily temperature) and heating operating over 12 ∼ 16 hours on coldest days