Choosing energy-efficient heating for older properties

Start With the Building, Not the Boiler

Edinburgh and the Lothians have a housing stock that is beautiful, characterful and occasionally infuriating to heat. Sandstone tenements in Marchmont and Leith, Victorian villas in Trinity and Morningside, stone cottages across East Lothian, plus plenty of 1960s and 70s estates on the edge of town. Solid stone walls with no cavity to fill, sash and case windows that whistle in a west wind, high ceilings that swallow warm air.

In older properties, the heating system is only ever part of the answer. If you upgrade the heat source before tackling the fabric, you will spend more money for less comfort. The sensible order of work is almost always: reduce demand, size the emitters properly, then choose the heat source.

Insulation and Draught-Proofing First

Before anyone quotes you for a boiler or a heat pump, deal with the obvious losses. A few priorities worth working through:

• Loft insulation to around 270–300mm where it can be laid safely. In top-floor tenement flats, the roof space is often shared, so check access and speak to the factor or other owners before you start.
• Draught-proofing sash windows with brush or bubble seals, plus a check on the meeting rail and the gap under the staff bead. Never seal a room completely if it has an open flue or a gas appliance needing ventilation.
• Slim double glazing or secondary glazing where full replacement is not possible or not permitted. Secondary glazing is often the practical route in conservation areas and listed buildings.
• Internal wall insulation on solid stone walls — genuinely effective, but it must be detailed carefully with breathable materials so you do not trap moisture against the stone. Get specialist advice before committing.
• Suspended timber floors — draught-proofing skirtings and insulating between joists makes a noticeable difference underfoot.

Once the losses are reduced, the heat loss figure for each room drops, and everything downstream becomes cheaper and easier.

Radiators and Pipework Are Usually the Real Constraint

This is the part most homeowners underestimate. A heat pump typically runs at 45–55°C flow temperature, while an older boiler may have been set to 70–80°C. Radiators sized for the higher figure simply will not deliver enough heat at the lower one. The rooms will feel lukewarm, the heat pump will work harder, and running costs will disappoint.

Ask for a room-by-room heat loss calculation in watts, then compare that with the output of your existing radiators at the proposed flow temperature. In many tenement flats, radiators are small and were fitted when fuel was cheap and expectations were lower. Some will need to be replaced with larger units, or supplemented with an extra emitter.

Pipework matters too. A lot of flats were plumbed in microbore — 8 or 10mm — which restricts flow rate. Upgrading key runs to 15mm or 22mm often makes the difference between a system that works and one that never quite gets there. Also budget for a proper flush and a magnetic filter; older systems carry sludge that will shorten the life of any new heat source.

Heat Pumps: Where They Suit Older Homes

Air source heat pumps are the usual choice; ground source needs land and significant excavation. The best candidates tend to be reasonably insulated houses with somewhere sensible to site the outdoor unit — not directly under a neighbour's bedroom window, since noise and vibration complaints are real.

In Edinburgh's conservation areas and on listed buildings, permitted development rights are often removed, so planning permission may be required. Always confirm with the local authority planning team before ordering equipment or booking an installer.

Tenements throw up particular challenges. There is rarely private external space, and communal solutions need agreement between owners — which is achievable but takes time and goodwill. A wall-mounted unit on a gable or rear elevation sometimes works, but check title deeds and factor rules first.

You will also need a hot water cylinder, as heat pumps heat water more slowly than a combi. Finding space for a 150–250 litre cylinder is often the single biggest obstacle in a flat.

Modern Boilers and Smart Controls

For many older Lothians properties, a well-installed modern condensing boiler remains the right answer — particularly where mains gas is available and the fabric is not yet ready for a heat pump.

• System boiler plus cylinder often suits older homes with two bathrooms better than a combi, which can struggle to supply several outlets.
• Weather compensation adjusts flow temperature with outdoor conditions and is one of the cheapest efficiency gains available.
• Smart controls work best set back rather than switched off and on. Gentle, longer heating periods suit solid stone walls far better than short blasts.
• Thermostatic radiator valves on every radiator except the one in the room with the main thermostat, and a properly balanced system so distant rooms actually heat up.
• Smart TRVs are worth it for rooms used occasionally, such as a spare bedroom or a study.

A Sensible Order of Work

If you are planning over the next year or two, this sequence saves money and headaches:

• Draught-proof and insulate what you reasonably can.
• Commission a room-by-room heat loss survey.
• Upgrade pipework and radiators where the figures demand it.
• Choose the heat source that fits the building and your budget.
• Set up controls, balance the system and commission it properly.

Do it in that order and you will end up with a warmer, quieter home that costs less to run — which, in an Edinburgh winter, is worth every bit of the planning.