ᐅ Summer in a penthouse apartment!

Hello,

we are currently looking for a condominium. At the moment, we are considering a penthouse apartment that is planned to be built according to the 2016 Energy Saving Ordinance (EnEV 2016).

Since we currently rent a duplex apartment, we are familiar with the problem of summer heat inside the apartment. Every summer, we experience 3-4 weeks with temperatures up to 30°C (86°F) in the living room (fortunately, the bedroom is on the lower floor). The current building dates back to around 1997.

Both the new and the old apartment have a southern exposure. However, the new penthouse would only be exposed to the sun from morning until noon. The duplex apartment receives sunlight on all sides, from morning until evening.

Now my question: Is it true that new penthouse apartments do not heat up as much because of the insulation? I find it hard to believe; if the summer sun shines for 2-3 days straight, wouldn’t the heat eventually penetrate inside and stay longer?

Second question: If we consider installing air conditioning, would this comply with the 2016 Energy Saving Ordinance? On the Energy Saving Ordinance website, it says: “The reference house is not equipped with cooling.” That made me uncertain.

Thanks for your help,
I am still quite new to this field.
Best regards, Jan

It definitely also depends on the installed windows and the possibility for shading (external roller shutters or blinds).
We also live at the top floor and still rent. The apartment has many large windows. Certainly nice and bright, but since shading is only possible from the inside during summer, it also gets warm.

Before summer, I had my attic apartment insulated according to current standards.
I no longer have skylights but do have several regular windows. Direct sunlight is minimal or blocked by exterior roller shutters.

Here’s my experience: when you block out the sun with the shutters, the apartment stays noticeably cooler for several days. That means if there are 4-5 sunny days in a row with the sun beating down on the roof all day, it doesn’t get excessively hot.
Thanks to a new room layout, I can now cross-ventilate the entire apartment quite comfortably, which lets the heat escape quickly.
After those 4-5 days, though, it gradually gets warmer inside, reaching typical attic apartment temperatures.
From what I can tell, this is not due to the insulation itself, but simply because during prolonged heat periods there’s nothing left that cools the temperature below a certain point.
In a ground-floor apartment, the earth surrounding or beneath it can help cool things down again. But with an attic apartment, you mostly don’t have anything that can cool it from below.
So if there’s a week or more of constant heat in summer, the indoor temperature at night will still be around 25°C (77°F) or even higher.
There’s simply no way around that.

If there’s a rainy day or a good thunderstorm in between, the indoor temperature resets to baseline, and it would take another 4-5 hot days to make it uncomfortably warm again.

In my opinion, this is all quite bearable. I’m also a fan of attic apartments and don’t mind summer heat or the sounds of rain and wind—in fact, I find them quite pleasant.

Since I’m not exactly sure what insulation is specified in the 2016 Energy Saving Ordinance (EnEV), I have 4cm (1.5 inches) of mineral wool and 14cm (5.5 inches) of rigid foam insulation on the roof.

Thank you for your feedback. I will check whether the roof windows have roller shutters.

Can anyone share their thoughts on air conditioning? Split systems aren’t too expensive, and if you run the unit for 2-3 hours before going to bed in the evening, I think the electricity consumption is justified. It’s better than sweating through the night. I honestly can’t imagine that air conditioning is banned under the 2016 Energy Saving Ordinance.

Hello,

our "old" apartment is also a top-floor flat with east-facing rooms (bathroom and kitchen) and west-facing rooms (living and bedrooms), built in 2000.

We have successfully managed the summer heat using only thermal roller blinds on the skylights (inside-mounted) and shutters on the regular windows.

We stopped using shutters on the skylights due to bad experiences within the family (my sister now knows almost all the service technicians of the (quite reputable) window manufacturer by first name).

Does the planned new apartment even have skylight windows? These are extremely heavy in typical sizes because of the triple glazing and, in some cases, can only be opened electrically...

In my opinion, a top-floor flat insulated to current standards should be comfortable to live in during summer from a thermal perspective.

Best regards

So, an air conditioner is not necessary just for a few days a year. It wouldn’t be worth it for me.