New build glazing and overheating. Any tips?

onrail

Were looking to get started on our new build shortly and I'm starting to have serious worries about the potential for overheating.

There will be beautiful views to the Southeast, so we oriented the house and a huge amount of glazing towards this.

All I'm hearing from people who built recently is that overheating is a huge problem, and I can only imagine it'll be brutal for us with all the windows.

Any advice? Is air-con a must in this case?

sydthebeat

Design design design.

You can easily design for passive cooling, and include passive shading like brise soleil etc

Mellor

Huge windows means large heat gain. But it also means large heat loss.

What kinda of insulation targets are you building to? If you are aiming building regs, I can't see it being an issue. If it was passive haus levels of insulation, then it would need to be considered.
What did your architect/designer say?

Biker1

Overheating is an issue in houses built to the current regulations that have a lot of glazing. I find myself having to specify air conditioning when doing the provisional BER because the designer has not considered overheating when designing the project. Needless to say the client is not happy to have to spend more on another system and the designer is also unhappy that their design is questioned by a mere BER assessor.

You can achieve a lot with slatted shades over South facing windows. The real problem comes around midday and light penetration is minimal at this point so easy to shade out. No amount of shading on the inside is worth an ounce of suitable shading on the outside. Has to be calculated and designed in at the start.

onrail

https://www.boards.ie/discussion/comment/122324257#Comment_122324257

Looking at full cavity fill insulation and similar underfloor, so I guess to regs rather than passivehaus.

Designer has been pretty hands off which worries me. When pushed, they have recommended exterior retro fit shading rather than any alteration to the structure plans.

onrail

All I've heard from my designer is that aircon isn't practical in a domestic new build so I hadn't investigated it further. Would it be worth speaking to suppliers about Aircon options?

Mellor

https://www.boards.ie/discussion/comment/122325351#Comment_122325351

Air con is entirely practical in a domestic new build. Far more practical than a retrofit.

But air con is entirely unnecessary in the Irish climate. Unnecessary energy load in summer.

If the house is correctly designed with appropriate shading there should be no need for Aircon. If Aircon is specified then your architect is a clown.

MacDanger

You could consider an air-to-air heating system (rather than the more common air-to-water) as this also allows for cooling as well as heating

fits

brise soleil should be enough! It’s not even a big deal this time of year as sun is so high. It’s in April that we can struggle a bit. Not this year though.

mike_2009

I'm building a passive house currently with brise soleil and air to air for space heating and cooling. Heating Engineer said two indoor cassettes would be enough, 1 for the open plan area and 1 for the office (a2a). The sun will likely cook your floor and this is the heat that will release later in the day / overnight. There are window films you can add that really help / ask your window supplier about options / what might affect warranty etc to get some mitigation that way. Also get some advice regarding adding Brise Soleil structurally if you aren't too far along to do that now so you have the option later. You can add removeable ones and only put them up in the summer etc. Passive Stack is the best way to cool down in the evenings and draw some heat out of the house, open low windows and high windows to create that breeze. I've Velux at the top of the landing and in the open plan area to purge excess heat / smoke when I burn the chicken….!