Hi we need some urgent advice about heating our MBC new build house. Basically we are having the slab done at the beginning of Nov and we are getting conflicting advice as to whether we need heating upstairs. We are building a modest 180 sqm three bed house, triple glazed windows, air source heat pump, underfloor heating and a MVHR with solar pv's on the roof. We have been advised my MBC we won't require heating upstairs only electric heated towel rails but Earth Save Products have emailed saying the following. Any advice would be welcome.
Will you be having any heating on the 1st floor? (e.g. Radiators). My reason for asking is that it will impact your RHI payments (reduce them). If nothing is going on the 1st floor, do you want the ASHP sized to cater for the heat loss from the Ground Floor only? If not, and you are relying upon heat migration to provide for the 1st floor, you will need to put all of the heating for the whole house in via the ground floor. This may make the Ground Floor too warm or the 1st floor may not get adequate heat migration to heat it. As you are also having an MVHR system, when it is cold outside, the incoming air will be lower temperature than the air leaving the house. This will cause a noticeable cooling of the 1st floor non-wet rooms and you may need supplementary heating.