3 times this summer I visited people who have done a new build in the last year. All houses have a savage BER etc
the one compliant all 3 had was that the house simply got too hot on warm days and some were even thinking about having to fit air conditioners in certain rooms, they were annoyed at this as extra money and retro fitting etc.
all houses had the air to water systems
I thought new houses were supposed to maintain the temp set.
are new houses too well insulated for relatively warm summer days?
Insulation works both ways; a well-insulated house will remain cool on hot days.
(Unless, of course, you have a heat source inside the house. In which case, turn it off.)
Overheating in summer is often down to glazing - particularly when large windows are south facing.
Not in Ireland, but I have an energy efficient house, it maintains a steady 22-23c all year around. In Summer the shutters on the south side will descend to block the direct sun light to prevent heat coming in. Works fine and no need for air conditioning.
This is one of the issues with the Part L compliance vs the likes of a Passivhaus standard. The Passivhaus methodology does look at overheating and how to tackle it via house orientation, glazing orientation , shading etc.
In a nutshell its often down to
Glazing - Quantity, size , orientation and complete lack of external shading or roof overhang to block peak summer sun from coming directly in.
Thermal Mass - If you have exposed thermal mass it acts like a heat sink , increasing thermal mass in homes would mean going for external insulation , internal blockwork , concrete floors etc all exposed , it acts link a big heat sink and smooths out the peaks and troughs of daily temperature changes.
Heating System - Poor or incorrect control , lots of people going for underfloor which is great but you need to know how to run and control it correctly or you can overheat in the shoulder seasons.
I live in a new house with a high BER. Taking my cue from people who live in warm countries, I simply pull curtains and open windows as required during particularly hot weather. I have one room that is mostly glass on two sides, facing south and west. As a temporary measure when I moved in I hung 4 individual curtains on one rail (as I couldn't afford custom made ginormous curtains at the time). I've kept that arrangement, as it works great for me - I can pull the curtains in different arrangements if I need to if it's particularly hot.
If I'm not going to be at home all day I lock the windows on the "vent" (to allow whatever bit of air that might be around come through) and leave the curtains/blinds closed on the south and west windows.
If I had lots of spare cash, and it wouldn't look odd in a housing estate, I'd go for external shutters everywhere.
its down to Solar gain from the windows, they should get in touch with their architect and let them know that they aren't very good.
some kind of solar shades should have been allowed for in the design.