We have been living in our home for a year now, so have seen both summer and winter, and we are now looking to solve the heating and cooling problems we have.
The walls and roof of the house are well insulated, and upstairs only has Velux windows, so apart from a brief spell when the combi-boiler stopped working (blocked condensate pipe) upstairs never has a problem with heating.
The open plan downstairs however is laminate flooring on concrete with minimal insulation, so the floor is always cold, and it's always a struggle to get it to feel warm in winter. Even with the heating water turned up to 80°C (176°F), the downstairs radiators fully on, and the upstairs radiators cold, a huge temperature differential remains.
So far we haven't had many problems with downstairs being too warm in summer, but upstairs can get uncomfortably hot, especially in our bedroom.
Neither of us sleep too well if too hot, so we are currently looking at options for air-conditioning. I am concerned about our environmental footprint however and would prefer a more sustainable solution if possible.
All radiators except the upstairs bathroom towel radiator (which acts as a bypass radiator) are thermostatically controlled. We will probably convert them to smart TRVs at some point, but this is unlikely to help with the problems described here.
Downstairs consists of a small toilet room (2m²/22ft²), plus a large open plan area consisting of living and dining areas, stair well and kitchen which is also open to the conservatory (39m²/416ft²). All external doors open into this area.
The central heating is relatively new, so the condensing gas combi-boiler is quite efficient. It has a heat output of 24.9kW (to heat 77m² / 826ft² of house) and a SEDBUK rating of 90%.
In the UK gas is much cheaper for heating than electricity, we currently pay 3p/kWh for gas (at 90% boiler efficiency) and 11p/kWh for electricity (that's 3 & 16 cents/kWh at current exchange rates) so we would prefer the bulk of the heating load to be carried by the gas central heating.
Down the line we would like under floor heating downstairs, but we can't justify that right now. We will also eventually get around to replacing the patio doors and the conservatory, which should help with insulation downstairs, but again those are longer term plans.
How can we equalise the temperature between upstairs and downstairs?
I thought of just fitting an insulated duct and a fan which extracts air from upstairs and pipes it downstairs, but the only place I could fit such a duct would be in the stair well, and it feels like the air would just end up circulating straight back upstairs. Other than that we would need to take a duct outside, which feels like a lot of work for an indeterminate benefit.
We have sought out quotes for a standard split air conditioner unit to cool upstairs, but that won't help with heating downstairs and I'm not happy about the environmental impact.
I was hoping that there may be solutions which could pump heat from upstairs to downstairs, but I don't know if split air conditioner systems can be configured to take advantage of temperature differentials like this.
- Note, I'm not looking for product recommendations, or someone to do a complete analysis of our situation, the detail is more to illustrate an example of the more general problem. What I am looking for is what would be considered a sustainable solution to the more generic problem of equalising temperature throughout a house with differing levels of heating and insulation.