MVHR - a householder's experience

Following a request for more information on Michael and Mo's low energy refurbishment - specifically about their part-house MVHR system - Michael has very kindly written a summary to share.

Just in case you are wondering, MVHR systems usually come in 2 forms. One is the whole house system which draws air from all the kitchens and bathrooms, and puts fresh, warmed air into bedrooms and reception rooms. The other option is to use "hole in the wall" fans with MVHR combined, just in bathrooms and kitchens.

Michael's system, on the other hand, sits between the two. As the air tightness of Michael's house has been improved well beyond the norm for a house of that age, the MVHR system may save some energy from the heating bill by retaining the heat from the outgoing air.

The most efficient of these systems can cost less than £30 per year in electricity to run (even if on 24/7) and can take less energy to run than the heating energy that they save.

Here's Michael's review of his MVHR system to date.

"TITON - HRV-1.75 Q+ unit"

Having installed this newly introduced unit 12 months ago, I am extremely impressed by the performance achieved to date.

The system extracts warm damp air from three areas, bathroom, en-suite shower and kitchen.  It operates on a "trickle" - 24/7 basis with switchable boost in the bath & shower areas.

In the "trickle" mode, it is inaudible but obviously in action when on boost.  The outlet vent in the dining room produces some noise & movement of air. This fresh air is pre-warmed by the outgoing stale damp air which is then vented through the roof, above the unit installed in the loft void. All loft trunking is contained in insulation jacketing to maintain efficiency.  As the house has a good air-tightness, over & above current building regulations, this, too, aids to the total efficiency of the system.

In summary, this efficient unit has produced a stable internal environment within our home. 

At present, no continuous monitoring of humidity levels has been instigated but it would be an interesting exercise to carry out. 

Perhaps one for the future!

Open house visits this weekend

15th September
• David Hill's zero carbon barn conversion in East Leake (superinsulated, renewable technologies and now an electric car)
There will be a tour starting at 2pm.

16th September (10 mins walk between this house and the 2000's house)
• 1950's ultra-low energy refurbishment (passivhaus) in West Bridgford
• Website (http://www.eco-retrofit.blogspot.co.uk/)
There will be a tour starting at 2pm and a later one from 3.30pm.

• 2000's house with cutting edge renewable technologies in West Bridgford, and a ultra-insulated extension under construction
• Website  (http://chargingtheearth.blogspot.com)
There will be a tour starting at 3.30pm.

Contact wbecohouses@gmail.com 

to book your place and to obtain location details.

Open house visits: more about the Peveril solar

Tina asked me to write a bit about one of the two houses that are on the visit of 16th September at 2pm or 3.30 pm. There is only a ten minute walk between the houses, so we have arranged is so that you can see one and then walk to the other.
http://wbecohouses.blogspot.co.uk/2012/08/open-house-visits-in-september.html

The Peveril Solar house is Net-Zero due to an interesting combination of solar technologies - Photovoltaic, Surya Sunbox, Kingspan vacuum tubes, underfloor heating and a Ground source heat pump. During the visit, the way in which these interact will be explained. There are other energy saving things to see, such an an induction hob, light tube, voltage regulator, partial heat reclaim.
Net-zero means that its entire heating and hot water requirements are met by PV power generation, annually. Yes, is entirely solar heated the whole year round using electrical and thermal storage.

Another interesting thing is that a new house extension is being built, being a unique form of construction. The architect is adapting structural insulated timber panel construction but applying hand built methods that avoid thermal bridging, making it ultra insulated, but keeping the walls to half the thickness of a brick-block wall. The extension will include one of the first domestic installations in the UK of PV-Thermal combi panels, the PV providing off grid electricity and the thermal being used to charge the borehole 16 storeys deep under the house.