I would recommend a Type 22 double panel double convector radiator for efficiently heating up large spaces. These dual panels and convectors really increase the surface area and airflow to heat the space evenly and they usually emit more heat than the Type 21 models, which have just one convector. But, keep in mind their size might not fit every space due to potential size constraints. While these radiators excel at their job, they're not without their challenges. They require regular maintenance to avoid efficiency drops caused by issues like airlocks or sludge buildup. And if you're looking for quick heat changes, they do warm up slower than forced air systems. Their size also means you'll need to think carefully about room layout since they require important wall space. Hot water radiators edge out steam radiators by using energy more efficiently to deliver steady, low-temperature heat. When you use a steam radiator that operates at a higher temperature, you're looking at greater heat loss. Hot water systems are also quieter and offer the consistent warmth you desire, unlike steam systems, which may become noisy. Choosing the right radiator depends heavily on the size of your area and what you need in terms of heating. For larger spaces, my favorite is definitely the Type 22 radiators. Their ability to output a lot of heat and do it efficiently can really make a difference in your comfort levels.