Boiler advice

@leedigings2

A house or an apartment?

Summers here are long and hot, so air conditioning is desirable/necessary. And as AC units can both heat and cool, this is a very popular option. Indeed, for most apartments this is perhaps the typical option. As these ACs heat and cool, they are heat pumps. However, most common is split AC units (I.e. per room), rather than large heat pumps for the whole property.

For a house, there are many options. In our village house, we have several splits (including a big one for the living room) together with a standalone pellet stove in case it gets really cold. I've decided I don't like the pollution and aggravation of wood-burning stoves or pellet stoves. The ACs are cleaner and easier. However, many folks love wood burning stoves, and it's quite a common option in village houses.

Your wood (or pellet) stove can be standalone, or it can be connected to central heating and radiators. (And it can be an ugly central heating-only one for a separate boiler room, or it can be a pretty living room one with a back boiler for the rads.) I reckon this is the most common central heating method in Bulgaria. Oil is possible (but not very common), as is gas. There is not a lot of mains gas here, especially in villages, but you can bury an LPG tank in your garden (a bit pricey).

A big heat pump is also possible, using air or ground. I'm not sure you can drive radiators, I'd imagine it's more typical to have ducted air or underfloor heating.

My nearest neighbours all have central heating with radiators. One is by pellet stove, one is by wood burner, and one has recently installed a gas boiler with buried tank. My well-drilling neighbour nearby is very handy and he built himself a new house of 200 m2 using SIPs, and he installed a ground-effect heat pump with underfloor heating. I reckon the cheapest option is a standalone wood burner (or pechka) which is very common here, and folks chuck one in the kitchen/living space and another in the bedroom.

Electric radiators are a thing too, but they're expensive to run.

Given my aversion to wood/pellet stoves, I've decided that I'm going to put in more split ACs, but make sure they are WiFi compatible so I can control them via Alexa or similar. And I'm planning to put a few kW of solar to contribute to the cost of running a bunch of units (even in Bulgaria, running 4 or 5 AC units will generate a hefty bill).

I recommend uPVC double-glazing and external insulation too, if you haven't already. Pretty much anyone renovating a traditional village house will do these upgrades.

@gwynj Hello again. Thanks for the info. I should have said that it is a 1950s house in town which has basically been gutted and is undergoing complete restructuring. At the stage of needing to decide on heating/hot water system. If I read you right you are suggesting electric (combined w AC) if wood burner is not sufficient/desirable? There is town gas available. But as I am not currently living there it's hard to compare running costs of gas and electric. Heat pumps sound good but big upfront cost.

@leedigings2

Technically, an air conditioner only provides cool air, a split unit (ie with an outside unit) is an air-to-air heat pump and provides both heating and cooling.  We have four properties here in BG and by far the cheapest way to heat them is via a split unit; in our main houses we do have wood burners but frankly we use them very rarely and only for the pleasure of seeing the flames - we have about ten cubic feet of seasoned oak which has been stored so long it's more like balsa wood.  You also need to bear in mind that Brussels is looking to ban oil and wood burners as they are heavy polluters.

Gas is expensive here and supplies may not be reliable long-term if Uncle Vlad has his way.  A decent split unit isn't cheap but it's well worth the cost - we prefer Mitsubishi Heavy, which we've found to be VERY reliable over the years.

External insulation is well worth having indeed - go for the thickest you can afford - and triple-glazed windows are more efficient than double-glazed.  Don't forget decent water boilers: we've found that the ones with stainless steel tanks offer the best bang for your buck; avoid the Italian ones like the plague - they're expensive and pretty but short-lived.

@JimJ Thanks. Can I ask your views on electric combi boilers? As you can tell, I am a novice!

@leedigings2

I've never had one, so I can't speak from direct experience, although I had plenty of gas ones in my time in the UK.  They're pretty expensive, and I'm not a fan of putting all my eggs in one basket anyway. Split AC heats much more quickly than any other method (and cools in the summer, of course) even in big rooms.  It's much simpler to install than CH.  Water heaters are likewise pretty cheap and quick.  (Relatively) cheap, efficient, versatile and rapid AC gets my vote every time - and my tenants love the low bills!

A woodburner is useful to have as a standby in case of the not-uncommon power cuts in BG.

@leedigings2

Central heating is very comfy, and it depends how much you like it, and how much you want to spend to get it. If you have town gas there, then perhaps a typical gas combi boiler connected to your hot water and a bunch of radiators might be a very nice option. A good time to install your rads is when you're starting a renovation.

However, Bulgarian summers are VERY hot. We find at least 2-3 months insufferable without AC/cooling (when we'll run them pretty much 24/7), and some folks run their ACs even longer. As @JimJ says, ductless split ACs are fairly inexpensive, and easy to install (and quite economical to run). Our house has a small 12000 BTU unit in each bedroom and a 28,000 BTU unit in the living room.

But once you've installed these units, you also have heating, almost as a free bonus. So then why go to the trouble and expense of installing central heating as well? Which is why many of us (including me and @JimJ) don't. If money was not an issue, I probably would have installed gas central heating with modern radiators and a buried tank in the garden.

Our new (well-insulated) apartment in Plovdiv has three 12k BTU Daikins, one for each bedroom and one for the living/kitchen. This winter we had the living room one running 24/7 for November-January and we only needed a few hours of top-ups in the bedrooms when it was especially cold. When we go out we leave it at 16 or 17, so the place never gets cold. The bill was 90 leva.

Most folks install the splits mounted high on the wall (because they're cheaper), but there are also pricey low ones that look more like storage radiators and perhaps are more comfortable in terms of air circulation and/or aesthetics.

And if you don't have central heating (and sometimes even if you do) the water is a separate system using an electric boiler (most commonly) or a (high power) electric on-demand water heater.

The other issue is that central heating is an all-or-nothing option where you spend a big chunk of money to install the whole system. For an incremental renovation, you can pop an electric boiler on the wall, and now you have hot water. Then you stick in a couple of AC units (living/kitchen and bedroom) and you've got some cooling and heating. You can add AC units in other rooms later. If you decide you need a bit of extra warmth, you can install a standalone wood/pellet stove quickly and easily (most houses have chimneys and outlets for stoves).