So, we’re starting to get some data from the house. Admittedly, we don’t have the most advanced monitoring systems - i.e. me with a pencil (apart from the MVHR temperature data, which is quite snazzy, of which more to follow in another post) - but think we’re capturing the key data.

The electricity and gas readings are shown from 23 January 2011 - by which time the MVHR, solar thermal and solar pv had all been commissioned properly - up to today’s date. Both of the solar readings are totals generated since date of comissioning.

1. Gas consumption - 5.8 HCF, or 180 kWh (@31 kWh per HCF) - note, this is just for cooking
2. Electricity consumption - 1,837 kWh or 14.35 kWh per day (over 128 days)
3. Solar PV output - 330kWh (since 9th January 2011)
4. Solar thermal output - 1,198 kWh (since 16th November 2010) - total hours of operation (i.e. pump running) is 845 hours. Therefore, the 7m2 of solar thermal is putting out an average of 1.41 kW

The electricity consumption looks high, making me wonder about the extent of our parasitic load and actual power consumption of the MVHR. Theoretically, the MVHR should only use a maximum of 140w for its two fans and there will have been some consumption when the heat pump was heating the hot water, but we need to install a reader to confirm this.

It is instructive to look at the net daily electricity consumption (i.e. incorporating input from solar pv) by month, below:

• February - 20.46 kWh
• March - 14.51 kWh
• April - 10.1 kWh
• May - 8.96 kWh

We will put up some key data from the MVHR datalog soon. Most notable trend so far is impressive stability of internal air temperature.