What you need to know when buying radiators for your home
Stelrad offers double and triple-panel compact radiators in traditional mid-century 'mattress' styles at excellent prices. Accord Type 22 double panel, 450mm x 1100mm in white, €156.95, suppliers include screwfix.ie.
Choosing your radiators for a renovation, new-build or one-room flip, there are a few basics to consider and I’m going to cover wet central heating (CH) here in both purely plumbed varieties. Getting the right heat emission for your rooms is a complex business, so always lean into the advice of your trusted heating engineer.
First of all, are we retrofitting to a set position or is there a choice in the sizing? The physical size of the radiator isn’t the only thing that determines its heat output. If you are just swapping out a radiator for one in the same BTU range (British Thermal Units) you won’t need to worry about up-scaling your boiler output. How and ever, adding several new radiator positions or going from single panels to double panels, it’s vital to ensure your boiler can handle the extra demand and reach along the extended central heating loop.
Be guided by your heating engineer as they should have a holistic understanding of the house and its CH character and energy efficiency.
If you have made serious insulation improvements (say adding EWI or dry-lining), your BTU demand may have fallen, and we can trim the flow down at the valves. If you are using a heat pump (HP for air, ground or water source) operating on lower, less reactive water temperatures of 40C-50C — this will inevitably influence your choice of suitable radiators. Your supplier and installer can determine if your existing radiators are large enough to handle HPs whatever their source. Generally, a heat pump will demand large existing panels in older houses, or full replacement with a super-conductor like aluminium.
To get started estimating the size and character of any new rads, we can use a BTU calculator based on the size of the room, any window openings, its aspect and the insulation quality of the walls, floors and ceiling. There are dozens of simple tools online, many linked to supplier websites.
We want to round the BTU figure up not down, to ensure the radiator can comfortably cover the room. Double panel radiators will neatly double the BTU with a minimal change in depth.
Keep in mind, with twice the size, comes twice the weight. When ordering replacement radiators ensure you know our left-pipe-centre to right-pipe-centre, and wall-to-pipe centres — your supplier can guide you. Returning a radiator — well, it’s heavy and if the mistake is yours, you’ll most likely be paying for it even with a refund for the rad itself. Ordering online, get it right the first time.
Unless you have pipes and valves in place, we will be deciding on valves to control and complement our new rad’. Every radiator should be detailed control using thermostatic-radiator-valves (TRV) or dedicated zone regulation through superb heating controls singing with in-room thermostats.
TRVs attached to the radiator now come in discreet, heritage finishes as well as the familiar white wheel style. Look up varieties from Milano, Admiral and Windsor. Your valve choice, manual or thermostatic will increase the width of the radiator overall (or its length in a vertical).
Ensure you know down to the millimetre where the pipes and valves will land. Dual-fuel radiators are largely used in bathrooms and can be part of your wet CH loop while having an independent electric element when you just want to cosy up the en-suite on a cooler morning.
Again, the BTU demand should be worked out carefully. Retro-fitting TRVs can be handled by a seasoned DIY amateur, otherwise have the plumber in, and ask for a deal for several valve changes.
Tall radiators with a thrust to the ceiling are most familiar in bathrooms with a squeak of space for wall mounting anything. Anywhere in the house, verticals will be up in your eyeline, but they do leave more room for other furnishings in the surroundings.
Painting them the same colour as the wall, they can recede while delivering a handsome design feature that won’t overpower the room. Otherwise, you can play the piece up in a bold colour in a gentled industrial vibe or as a form of wall art — it’s completely up to you, and it’s worth considering any radiator as an impactful design element.
Heritage radiator types can also reach for the sky. There are 19th-century-style cast-iron sectional Bundy-loops made originally for early steam radiators, in towering vertical columns on supporting, traditional Queen Anne legs.
They look fantastic in a front hall, playing off the ascent of the stairs and a higher ceiling. Ask your engineer about the convection question with any vertical radiator as it’s generally accepted that there’s better convection around the room with long, lower horizontal styles.
Rippled 1960s "mattress" varieties of radiator were an aesthetically invasive thug, blocking wall positions from furniture and interfering with the appearance of curtains as they squatted, cheerfully conducting draughts from window positions to the whole room. Only use wasted space under windows with good “U” values if it suits you.
Going from horizontal to vertical or vice-versa in a retrofit, the pipe positions will have to be moved, an extra expense, especially chasing back into the floor or walls.
Schedule this work for when the floors are already up. The wall must be able to bear the load. The position of studs in a frame wall covered in plaster-board will have to be established carefully and the correct strong, brackets installed, especially with a long, lofty vertical radiator — enormously heavy once filled with water.
Different radiator materials offer slightly different thermal characteristics. Cast iron (new or restored) heats up more slowly than steel or aluminium. Your boiler will work harder and for longer initially to warm up the cast iron and then throw heat out to the room.
A dense material, iron retains and radiates as well as convecting accumulated warmth. Steel radiators are not only economical but respond more quickly to the settings of your heat controls.
A reactive conductor, steel is widely available in a huge range of styles and is perfect for quick heat-up with conventional gas or oil CH systems.
Still regarded as the new kid on the block, pricier aluminium convects brilliantly with relatively little hot water. Because these radiators are lighter than cast iron or steel, they can overcome the challenges of a daintier wall and the prospect of a vast rad’ as they wildly outperform other materials and in smaller sizes.
Offered in recycled materials aluminium is a popular sustainable choice that can outlast steel, and convects quickly and efficiently, but that does come at a premium.
In terms of colour, you can choose from a spectrum of around 200 RAL shades for your radiators with some suppliers, while others will have a range dedicated to that particular collection. Coordinate or contrast, it’s up to you. Farrow & Ball paint colours in their specialist Radiator Paint has a high resistance to heat and is featured on Milano heritage inclined radiators with companies like bestheating.ie.
The loading on the ticket price for a 660mm high example is as much as €230.
Ensure any coating doesn’t reduce the heat output of the radiator, especially if you plan to paint a unit up yourself in any metallic shine.
Mottled, burnished, polished, textured effects and galvanised finishes, featured by top companies including The Radiator Company in the UK, will again heat up the price but for a special project may be worth the extra investment to tailor out a beautiful designer element.
Always buy a primed radiator ready to take dedicated radiator paint if you’re trying to save money, as that first surfacing can be complex to get right. Lacquered raw metal cast-iron and steel radiators are stunning if you prefer a vintage, honest touch. Look for oval columns to achieve the art deco renaissance styling that’s everywhere for 2024.
A factory-applied finish will outshine that first DIY dabbling, so where you have the choice and can afford the extra bespoke detailing, I would work with your supplier, and start with blacks, whites or a standard metallic.
