Yo, we have had a couple of energy audits done before. I don't want to say don't do it, because there may always be something more we can learn, but we have already gotten a good idea where we stand in terms of energy efficiency...
- A lot of our appliances are inefficient, most especially our various fridges. They cost money to replace. Not worth it unless we can calculate that we will save an equivalent amount.
- We waste a lot from people not turning shit off. This could be the grill when it is not cooking anything, the coffee machine/tea urn at night, the lights, the PA, computers, monitors. This is where our main potential energy savings could be made if there was a way to get everyone to understand and act in the proper & sensible way.
- Insulation - could be slightly better in places. A good DIY job for someone with experience.
- As for renewables, here is a quote form the last guy to come and size us up for wind & solar etc:
... as a renewable energy installer I would be uncomfortable
recommending that you spend money on RE until you've solved the waste
So, in terms of a better heating solution, given your requirements and
the fact that there's not much you can do about the structure of the
building and insulation and so on (apart from the shutters as
mentioned), I would probably recommend a CHP [combined heat & power] type setup. Preferably
running on biomass or waste vegetable oil.
Given that you are tenants and don't want to mess with the existing
systems too much, an external plant, with ducts taking warm air into
the east side of the building (basement and cafe area) will probably
be of most use.
Realistically, forget about heating the upstairs hall with anything
other than the big gas boiler. Just try to manage your usage of that
place so that you're not heating it unnecessarily.