Is there an obligation to renovate according to the Energy Saving Ordinance despite various prior efforts by the owner?

Hello,
we have been living for 14 years in a two-family house built in 1929 as tenants (brother-in-law downstairs, us upstairs).
The house is now to be sold and we will get it at market value according to the appraisal (appraisal available).
Since we have been living in the house for a long time, some renovation/refurbishment measures are also known.

Nevertheless, I would like to ask whether any refurbishments could still be imposed on us in the next 2 years?
The appraisal states "apparently no retrofitting obligation for buyers according to the Energy Saving Ordinance"?!
But what are the experiences here?

The following is known to me or I have knowledge from the landlord:

- 2002 bathroom renovations/interior renovations with "light internal insulation" (drywall with Styrofoam covered) and new heating supply lines (insulated in the basement)
- 2009 attic (cold roof - hipped roof) covered with 10cm Styrofoam and 18mm OSB for walking on
- 2011 new heating boiler (oil condensing boiler elco), buffer tank, pumps and expansion tank
- 2011 solar system on the south roof for water heating
- 2016 complete renewal of exterior plaster (down to the masonry (solid brick - no insulation)).

Windows are from 1978 and so far okay (double glazed, external roller shutters towards living space - partly insulated)
Basement is sandstone in the ground, above that concrete (basement protrudes 0.5 stories out of the ground) - ceiling not insulated.
Roof construction is very simple: rafters, battens, tiles.

I would appreciate a brief info, or info on a similar topic.

Thank you very much and have a nice Sunday!

Best regards, Matze

Renovation obligations upon change of ownership exist only for uninsulated top floor ceilings or alternatively the roof (if minimum thermal protection is met, old insulation is also acceptable ==> consult energy advisor). Oil heating not required, provided it is condensing. Otherwise, the pipes must be insulated - in unheated rooms. To my knowledge, there are no further obligations.

The expert is right, all good. Apart from that, I wonder who would actually check if there is a real obligation to renovate. I bought an old building almost four years ago and insulated the top floor ceiling, for example. But simply for comfort and efficiency reasons, no one ever cared about that.

Mandatory even for rental. But it shouldn't, right?