Old Saint Paul’s is a big, B-Listed, late Victorian church close to Edinburgh’s Waverley Station. As it lies in the precipitous shadow of the Old Town and has tall buildings on either side, the interior is dimly lit even on the sunniest days. Unsurprisingly, its huge interior gets very cold.
For years, our ancient gas-fired heating system had been a cause of concern. It had become increasingly ineffective, was periodically breaking down, and was almost irreparable. It was also complex and costly to operate, and seriously eco-unfriendly. Complaints about the coldness of the church were frequent, and the cold had started to keep members of the congregation away.
Earlier this year, the Vestry therefore determined that we should replace the current system with one that would be more effective, better for the environment, and less expensive and complex to run.
The first step was to commission a feasibility study of options for low-carbon heating systems for the church from a firm of consulting building-services engineers. Their report offered us two options.
Underfloor heating
The first option was electric underfloor heating powered by an external air-source heat pump. However, this option had several drawbacks. It would be costly and disruptive to install and would require a new floor, requiring the involvement of an architect and other professionals in a complex consent, design and construction process. Our constrained city centre site also meant that there was nowhere suitable to locate the associated air-source heat pump.
In addition, underfloor systems build up and release heat slowly, and a constant-heat system would be very costly to run unless the main body of the church were to be used frequently. We therefore rejected this option.
Electric radiant heaters
This second option met all our objectives. Electric radiant heaters use infra-red radiation, like the sun. This heats the objects the radiation strikes – the people – rather than the air around them (which is what the old gas-fired system did). Moreover, the heat is instant.
Electric radiant heaters and their power cables could be discreetly mounted in the church interiors, making the system a light-touch and wholly reversible change to the building, which is a key consideration in building conservation terms. It also involved a lower capital outlay and lower running costs than underfloor heating and was simple and fast to install.
Such a system also allows for zoning of the church, so that, for example, we can heat only one of the chapels or just the front of the Nave. This is both cost- and energy-efficient.
Having obtained proposals from three potential providers, we settled on the one we considered best combined an impressive track-record with affordable cost.
The new system
We have used three types of electric radiant heater in the church: under-pew heaters for the Choir, wall-mounted heaters in the two chapels, and chandelier heaters in the Nave. Chandelier heaters were needed in the Nave because the heat from wall-mounted heaters would not have reached those seated close to the central aisle.
The chandeliers hang in two rows down the Nave, and each pair is separately operated. They are positioned high enough not to block the congregation’s view of the pulpit, the lectern, or our gallery-mounted live-stream cameras.
The chandelier heaters are hexagonal, and each one has six burners. We can switch on all six burners, or just three, depending on the level of heat required. The chandeliers also have lights: six above the burners, and six below. The lights are operated separately from the burners. Ideally, we would have made the lights dimmable, but this would have added to the cost and, sadly, we have other more pressing calls on our funds.
The visual impact of the chandeliers is considerable and, inevitably, reactions to the change are mixed. Personally, I think the chandeliers enhance the look of our cavernous Nave. Photos of the chandeliers in action make the lights look far more glaring than they actually are. One downside, though, is that the burners glow when in use (a fairly soft orange), which affects services during which the church should be in darkness. But we reckon this is a small price to pay for the ample warmth they give.
Overall, the system does everything we wanted it to: it keeps us warm, it decreases our environmental impact, it is easy to operate, and we believe it will significantly reduce our running costs.
If you would like to talk to us about electric radiant heating, email us at property@osp.org.uk.
Mark Gibson, Old Saint Paul’s Property Committee Convenor
