ᐅ Bathroom in an older building: Is a second radiator necessary? And if so, should it be electric?
Created on: 2 Sep 2025 08:01
J
jverbeek
Hello everyone!
After reading this forum for a long time, I finally created an account to ask a question!
We are currently renovating an old building from 1959. We combined the previously separate toilet and bathroom but mostly kept the wall between them, only making an opening between the bathroom and toilet. These rooms are located along an uninsulated 29cm (11.4 inch) exterior wall and have a total area of about 7.5m² (81 square feet). Here is the floor plan:
Originally, there was a panel radiator under the window. We plan to install one again—a Type 22 radiator, either 100x60cm (39x24 inches) or possibly 120x60cm (47x24 inches). However, we are unsure if this single radiator will adequately heat the newly connected toilet area. The wall (14cm (5.5 inch) sand-lime brick) between the bathroom and toilet runs up to the ceiling, with only the width of a door opening—but no door installed—allowing passage. The warm air would have to flow “around the corner” to the toilet, which seems unlikely to me. Therefore, we are considering adding a second radiator to ensure that the toilet is always comfortably warm.
I was thinking of a towel radiator on the right side of the door leading into the whole room (opposite the bathtub). Would that be sensible?
Also, would an electric towel radiator be an option? Unfortunately, we slightly overlooked this during planning, and the screed is already finished there—I would rather not break it up again. But if necessary, we will.
I’m looking forward to your opinions!
Best regards,
Johnny
After reading this forum for a long time, I finally created an account to ask a question!
We are currently renovating an old building from 1959. We combined the previously separate toilet and bathroom but mostly kept the wall between them, only making an opening between the bathroom and toilet. These rooms are located along an uninsulated 29cm (11.4 inch) exterior wall and have a total area of about 7.5m² (81 square feet). Here is the floor plan:
Originally, there was a panel radiator under the window. We plan to install one again—a Type 22 radiator, either 100x60cm (39x24 inches) or possibly 120x60cm (47x24 inches). However, we are unsure if this single radiator will adequately heat the newly connected toilet area. The wall (14cm (5.5 inch) sand-lime brick) between the bathroom and toilet runs up to the ceiling, with only the width of a door opening—but no door installed—allowing passage. The warm air would have to flow “around the corner” to the toilet, which seems unlikely to me. Therefore, we are considering adding a second radiator to ensure that the toilet is always comfortably warm.
I was thinking of a towel radiator on the right side of the door leading into the whole room (opposite the bathtub). Would that be sensible?
Also, would an electric towel radiator be an option? Unfortunately, we slightly overlooked this during planning, and the screed is already finished there—I would rather not break it up again. But if necessary, we will.
I’m looking forward to your opinions!
Best regards,
Johnny
Thanks for your answers! Since the bathroom isn’t very large, it doesn’t necessarily have to be a “comfort zone” with 24°C (75°F). But it would be nice if it could be 20°C (68°F) everywhere, not just in the front area, while near the toilet it’s around 16°C (61°F). We don’t have much higher expectations than that.
The concerns about mold in the toilet are actually good points that I hadn’t considered before, thank you!
We could also easily go for a Type 33 radiator under the window; that would fit the space. It’s true that the towel radiator is often covered with towels, but I still think it’s a good idea.
We also have the situation where a second water-heated radiator would be connected under the window, but only a 12mm (½ inch) pipe is available there. Would it even be possible to connect a towel radiator with approximately 916 watts (at 75°C / 167°F) over 3.50 m (11.5 ft) using a T-piece to this 12mm (½ inch) pipe, or would the pipe need to be larger?
The concerns about mold in the toilet are actually good points that I hadn’t considered before, thank you!
We could also easily go for a Type 33 radiator under the window; that would fit the space. It’s true that the towel radiator is often covered with towels, but I still think it’s a good idea.
We also have the situation where a second water-heated radiator would be connected under the window, but only a 12mm (½ inch) pipe is available there. Would it even be possible to connect a towel radiator with approximately 916 watts (at 75°C / 167°F) over 3.50 m (11.5 ft) using a T-piece to this 12mm (½ inch) pipe, or would the pipe need to be larger?
jverbeek schrieb:
But it would be nice if it were 20°C (68°F) everywhereEven at a room temperature of 20°C (68°F), I would be concerned that the corners of the rooms might cool down too much, potentially leading to mold over time. That's why I would also install a proper radiator on the bathroom side.Similar topics