Renovation - Insulation / Ventilation etc. sensible?

Hello everyone,

we have a house from the 80s and wanted to renovate it extensively. For this, we consulted an energy advisor to get expert information. Ultimately, his analysis concluded that we should redo the roof, insulate the facade with a [WDVS], insulate the basement, and replace the windows. In addition, a ventilation system should be installed and the heating technology switched to a heat pump.

That all sounded great, of course...

Until a few days ago when we saw a report on NDR that said a [WDVS] is quickly flammable, the ventilation systems become full of germs and bacteria after a relatively short time, and that the costs, for example for filter changes, are so high that an extensive renovation does not pay off. Especially because of the germs, etc., we were quite shocked and now don’t know what to do or whether we should do anything at all...

We hope that there might be some kind people here (especially those who are knowledgeable and experienced in this area) who can recommend which path we should take.

Thank you very much for all your advice, tips, or even questions!!!

Hello Schwebbs

well, I would reconsider the renovation once again. Or rather, get another "expert" involved. What training did your "energy consultant" have?? Nowadays, unfortunately, anyone who has taken a weekend course can call themselves an energy consultant...

I had a similar case in my surroundings (house from the 60s): an energy consultant also recommended facade insulation and a new heating system. He said it would pay off after 15 years. A simple check of this calculation (cost of insulation divided by current heating costs) resulted in a payback period of 40 years. But that would mean having no heating costs for 40 years at all, and the loan interest for the investment is not considered either...
Well - you didn't have to calculate any further in this case...

Regarding the topic of ETICS everyone can have their own opinion now...
I’m currently experiencing it in a rental apartment... You live like in a plastic bag...
And the fire issue... Well - basically everyone should know how well or badly polystyrene can burn...

I can tell you something about ventilation systems in a few months. I’m definitely looking forward to having one soon. And as far as germs are concerned - logically you would also have to do without a kitchen and a bathroom! Just imagine what kind of germs can develop if you don’t clean!!
Sure, you have to clean the system regularly and keep the filters clean or replace them. But you also have to clean your oven regularly, your bathroom, ... , ...

But that is just my personal opinion

Regards
Micha :cool:

Hello,

....Ultimately, his analysis concluded that we should redo the roof, insulate the facade with an ETICS and the basement, and replace the windows. Additionally, a ventilation system should be installed and the heating technology switched to a heat pump.
That of course all sounded great...

A new construction project might almost make more sense. ;-) This EB is certainly not a building services planner and economic efficiency for the operator apparently is not the priority here.

...Until a few days ago, when we saw a report on NDR saying that an ETICS is highly flammable,..

There are also other insulation materials! ;-)

...that ventilation systems after a relatively short time are already full of germs and bacteria and that costs, e.g. for filter changes, are so high that extensive renovation does not pay off.

Aside from the alleged "germs," retrofitting a centralized controlled residential ventilation system with heat recovery in an existing building is already quite demanding and expensive, depending on the existing building construction!
Overall, one should carefully consider such a "general all-around approach" and, if necessary, rather focus on critical focal points.
Dealing with current energy prices makes little sense here; one should definitely consider a progressively increasing development.
Moreover, there is probably no better and safer investment than investing in one's own building at present!

...We hope that there are perhaps some nice people here (especially those knowledgeable and experienced in this field) who can recommend which path we should take.

I would doubt whether just nice people alone can really and sustainably help here. Probably only a thoroughly trained specialist will be able to assist. With just a few "keystrokes" on some EB software, you will hardly get further, as this example clearly shows.

Best regards

Hello everyone,

we have a house from the 80s and wanted to renovate it extensively. For this, we consulted an energy advisor to get expert information. Ultimately, his analysis concluded that we should redo the roof, insulate the facade with an ETICS, insulate the basement, and replace the windows. Additionally, a ventilation system should be installed and the heating technology switched to a heat pump.

That all sounded great, of course...

Until a few days ago, when we saw a report on NDR that said that ETICS is highly flammable, ventilation systems are already full of germs and bacteria after a relatively short time, and that the costs, for example for filter replacements, are so high that such extensive renovation is not worthwhile. Especially because of the germs, etc., we were quite shocked and now don’t know what or whether we should do anything at all...

We hope that maybe there are some nice people here (especially those knowledgeable and experienced in this field) who can recommend which path we should take.

Thank you very much for all your advice, tips, or questions!!!

Hello Schwebbs,

energy advisors with 'official' training must also advise on what they have learned. That means insulation is great, preferably on the outside with ETICS, new windows, insulating the roof, ... without any sense and unfortunately often without understanding ;-).

I take the position that an independent advisor (who unfortunately also is not state-funded) always fares better than those who took this weekend course. But back to the question.

It is difficult to make a statement without having seen the building. Houses from the 80s very often have a good structure to build upon.

Of course, if the wish is to have an energy-efficient house, then all measures must be carried out accordingly. If the objective is to optimize the existing structure, then there are still alternatives. I come from the eco corner, so my suggestions differ from those of the energy advisor.

If the roof is not yet insulated, I would also recommend this, but only if the attic is or will be used; otherwise, insulation above the ceiling of the top floor is reasonable and sufficient. If the roof is insulated, one should also pay attention to summer thermal protection; for example, glass wool is out—it keeps heat in during winter but lets heat through in summer.

A second important point, of course, is the floor to unheated rooms or earth.

As a third point, I see the facade and the windows. How old are the windows, does it make sense to replace or adapt them? Should the facade be insulated or not (depending on wall thickness, not necessarily economical). There are also ETICS that have no fire safety issues.

The fourth point is the ventilation system. Is this desired? Then there are several systems, central and decentralized ventilation systems. For renovation, decentralized ventilation systems are usually suitable, generally a central ventilation system is better but only if it can be optimally managed. Then the problem with contamination and germs is less problematic.

The fifth point is the heating. Here, the question for me is what you want. Should it operate fully automatically, or do you want to heat, for example, with firewood? Should there be solar assistance or do you want a heat pump? I can understand not wanting to install gas or oil heating anymore; heat pumps are very good devices, especially those that generate heat from outside air, which I only consider reasonable for very well-insulated buildings (passive houses and better).

Well, that’s enough written now!

best regards

K. Brodbeck

Hello,
I would not let myself be unsettled by a single report alone; unfortunately, these exist in both extremes...
In terms of the suggestions, these are really the usual measures, namely insulating the largest exterior surfaces (basement ceiling, exterior walls, roof surface), improving the standard of the windows by replacing them, and then considering replacing the heating system.
Regarding the improvement measures, it should certainly be said that the consultant should not only present all the measures but also examine the economic side and show you what each measure brings and how much is saved...
The same applies to the heating system; for a new building, a ventilation system with heat recovery and also a geothermal heating system can certainly be very interesting if this is planned together with the building. For existing buildings, especially if, for example, a gas connection is already available, it can certainly be more sensible and economical to provide a gas condensing boiler.
So ask the consultant again and have him work out not just one but different variants, or demand different proposals from him.
And as already mentioned, a consultation without inspection is difficult, but energy consumption (gas, oil, wood) per year, the size of the building, insulation standard, and type of heating system are essential information for further statements.