ᐅ Insulation in the 1970s Compared to Today, Modern Insulation, Heating Costs

I would be interested in an assessment of how much higher heating costs (in percentage) you can expect in a house built around 1970 with solid construction according to the standards of that time (including windows), compared to modern insulation as commonly used today.

Are there significant differences? This concerns exterior walls and the roof.

Where are the biggest heat losses likely to occur? Exterior walls, windows, or the roof?

Which renovations would be particularly necessary, and which ones less relevant?

Thank you

No one can really give you a definitive answer to that. Usually, the actual surface areas and their values are calculated. Then climate data and individual needs are also taken into account. It’s too complex for a simple statement.

What type of wall construction do you have? Insulating the roof is usually fairly straightforward and already provides significant benefits.

Meecrob schrieb:
..... Then there are climate data and individual needs to consider. Too complex for a simple statement.

Absolutely correct!
Additionally, extra insulation must always be evaluated in connection with the building services engineering. With a water-source or brine heat pump, one can often avoid excessive insulation measures; with gas condensing boilers, air-source heat pumps, or wood burning, somewhat more insulation is usually advisable! However, this should be targeted and purposeful. Usually, an adjustment of the heating system is necessary; otherwise, the "optimistically calculated" energy-saving measure will simply dissipate.

Best regards.

Ah, what do W- or brine heat pump and gas condensing boiler, air heat pump mean? To what extent does the heating system need to be adjusted according to the insulation?

These are IDE heating system types:
Ground source heat pump
Air source heat pump
Gas condensing boiler

Insulation reduces the amount of heat required. This may result in the existing heating system being oversized and operating inefficiently.
The energy savings achieved through insulation are therefore at least partly lost.