February 2017

The first three months

We like the house and it is working more or less as expected. We did have a problem with the heating in that the supplied Heatmiser thermostat that controlled the MVHR Duct Heater could only be set to integer degrees - 20 was too warm and 19 too cold! I replaced this with a Netatmo thermostat which has proved to be simple to use and the data provided helps us understand what the house is doing.
We have it located in our bedroom and the temperature is similar across all the first floor. It can be controlled from anywhere using an app or web browser.

In mid-December we installed another Far infrared heater in the lounge and this partially resolved the heating issues that were caused by the distribution of heat from the MVHR duct heater (see We've moved in! - December)
This is a 630watt panel and is connected via an Elgato Eve switch and power meter to a power socket. This means we can control it manually, via timing set periods or via various rules e.g. switch on if the external temperature is below 5 degrees. In practice it has been currently just set up to come on during the Economy 7 period. However with the stronger February sun and surplus PV generated electricity we have started diverting some of this to the heaters. This has the effect of raising the house temperature from our current 19.5 degrees base and delays the duct heater using imported electricity. The plot from the Netatmo application shows this effect. This shows a period of a week with diverted energy raising temperature on the 13th with no subsequent use of the duct heater (shown in pink). (note this is air temperature - the rapid rise and fall reflects poor heat capacity of air the surfaces of the structure change much less quickly and help buffer the air temperature)
netatmo plot

Ideally one would set up a system to automate diversions but currently I simply keep an eye of the solarcache monitor and intervene via my phone!

Solarcache plot