A conservatory typically has four exterior walls (including the roof) with significantly lower thermal resistance, resulting in a multiple of the heat demand compared to a living space with solid walls. For this reason, a conservatory is usually left unheated for energy efficiency.
Can anyone provide an approximate estimate of the heat demand for a wood-aluminum conservatory with about 90 m³ (3,180 ft³) of enclosed volume that is used as a living space?
It has a 30 m² (323 ft²) floor area, approximately 41 m² (441 ft²) of post-and-beam structure, 35 m² (377 ft²) roof area, all fitted with 1.0 thermal transmittance (U-value) glazing. The posts measure 5 x 12/16 cm (2 x 5/6 inches) (corners 16 x 12 cm / 6 x 5 inches), beams 5 x 10/16 cm (2 x 4/6 inches), rafters 8 x 20 cm (3 x 8 inches), ridge beam 14 x 34 cm (6 x 13 inches), all made from spruce laminated timber.
Many thanks for a brief indication of how much higher the heating energy demand is compared to a similarly sized living room built to old or new construction standards.
Can anyone provide an approximate estimate of the heat demand for a wood-aluminum conservatory with about 90 m³ (3,180 ft³) of enclosed volume that is used as a living space?
It has a 30 m² (323 ft²) floor area, approximately 41 m² (441 ft²) of post-and-beam structure, 35 m² (377 ft²) roof area, all fitted with 1.0 thermal transmittance (U-value) glazing. The posts measure 5 x 12/16 cm (2 x 5/6 inches) (corners 16 x 12 cm / 6 x 5 inches), beams 5 x 10/16 cm (2 x 4/6 inches), rafters 8 x 20 cm (3 x 8 inches), ridge beam 14 x 34 cm (6 x 13 inches), all made from spruce laminated timber.
Many thanks for a brief indication of how much higher the heating energy demand is compared to a similarly sized living room built to old or new construction standards.
S
Sebastian4 Jul 2009 07:26Surely no one understands this. At least none of those who have read it, and I count myself among them.
Best regards and I hope you get the help you need, unless you have already asked for advice at the hardware store or specialist retailer!?
Best regards and I hope you get the help you need, unless you have already asked for advice at the hardware store or specialist retailer!?
Hello Sebastian,
Thank you very much for your response. Unfortunately, I haven’t received any answers to my posts here in the house building forum so far... a pity. It seems my questions don’t quite fit here... but it was worth a try. Do you know a good forum for conservatories and building physics?
I had the conservatory calculated. Based on an assumed outdoor temperature of -12°C (10°F) and an indoor temperature of 20°C (68°F), it requires a heating output of 2800 watts, plus an additional reheating allowance for intermittently heated spaces. This means the heating load is about three times higher than that of a room in an uninsulated older building.
Well, heatable doesn’t mean heated all the time...
Best regards
Maddin
Thank you very much for your response. Unfortunately, I haven’t received any answers to my posts here in the house building forum so far... a pity. It seems my questions don’t quite fit here... but it was worth a try. Do you know a good forum for conservatories and building physics?
I had the conservatory calculated. Based on an assumed outdoor temperature of -12°C (10°F) and an indoor temperature of 20°C (68°F), it requires a heating output of 2800 watts, plus an additional reheating allowance for intermittently heated spaces. This means the heating load is about three times higher than that of a room in an uninsulated older building.
Well, heatable doesn’t mean heated all the time...
Best regards
Maddin
S
Sebastian7 Jul 2009 11:12Hi Maddin
I don’t think you’re in the wrong place here. It’s probably just that no one else has the same problem or/and the expertise with it.
I can’t recommend another forum, I only signed up here myself.
Just wanted to suggest you read your post again, maybe someone will respond after all.
Regards
I don’t think you’re in the wrong place here. It’s probably just that no one else has the same problem or/and the expertise with it.
I can’t recommend another forum, I only signed up here myself.
Just wanted to suggest you read your post again, maybe someone will respond after all.
Regards
About heating demand for a conservatory?
Hello Maddin,
- Often, the difference between the required heating power (based on maximum demand, without solar gains, outdoor temperatures of -14 to -16°C (7 to 3°F) depending on location) and the heating energy demand/consumption is blurred. A heated conservatory is not automatically an "energy hog" compared to a solidly built room. This is true mainly during peak load periods, for example, a New Year’s Eve party with outdoor temperatures around -20°C (-4°F).
I have already sat in a conservatory, enjoying coffee with my family in January on a sunny day, at -10°C (14°F) outdoors, wearing just a shirt and no heating.
Considering solar gains, and the significant reduction in heating days or hours, there can even be an energy benefit relative to the usable floor area of the house, especially if you can close the doors to the living room during cold winter nights.
More detailed calculations have been published, for example, by Prof. Marquardt (Buxtehude) online and in specialist journals.
Of course, you can calculate the peak heating demand for your conservatory. Please note though that with heating systems specific to conservatories, the arrangement is important (the heat source should be near the coldest spots, not just wherever the heating contractor happens to find the nearest pipe). For peak power sizing, approximately 300-350 W/m² (28-33 W/ft²) of usable area is recommended, and the glazing needs good air circulation so that condensation caused by rapid changes in temperature and humidity can dry quickly.
You can also decide not to spend cold nights in the conservatory, in which case a lower heating capacity is sufficient. But if you forget this decision later, don’t blame the conservatory or heating installer if the glass room doesn’t get warm.
Have fun planning—and even more enjoying your finished conservatory!
Spenke
Hello Maddin,
- Often, the difference between the required heating power (based on maximum demand, without solar gains, outdoor temperatures of -14 to -16°C (7 to 3°F) depending on location) and the heating energy demand/consumption is blurred. A heated conservatory is not automatically an "energy hog" compared to a solidly built room. This is true mainly during peak load periods, for example, a New Year’s Eve party with outdoor temperatures around -20°C (-4°F).
I have already sat in a conservatory, enjoying coffee with my family in January on a sunny day, at -10°C (14°F) outdoors, wearing just a shirt and no heating.
Considering solar gains, and the significant reduction in heating days or hours, there can even be an energy benefit relative to the usable floor area of the house, especially if you can close the doors to the living room during cold winter nights.
More detailed calculations have been published, for example, by Prof. Marquardt (Buxtehude) online and in specialist journals.
Of course, you can calculate the peak heating demand for your conservatory. Please note though that with heating systems specific to conservatories, the arrangement is important (the heat source should be near the coldest spots, not just wherever the heating contractor happens to find the nearest pipe). For peak power sizing, approximately 300-350 W/m² (28-33 W/ft²) of usable area is recommended, and the glazing needs good air circulation so that condensation caused by rapid changes in temperature and humidity can dry quickly.
You can also decide not to spend cold nights in the conservatory, in which case a lower heating capacity is sufficient. But if you forget this decision later, don’t blame the conservatory or heating installer if the glass room doesn’t get warm.
Have fun planning—and even more enjoying your finished conservatory!
Spenke
Hello Spenke,
Thank you very much for the link. The conservatory has been standing for several years now, and I can only confirm your experience. There is definitely something special about sitting at the coffee table in a T-shirt while people outside trudge through the snow in heavy winter coats at -10°/-15°C (14°F/5°F)...
But precisely for the situations you described (Easter, Christmas, New Year’s Eve, birthdays), we want the assurance of being able to use the conservatory regardless of sunlight. Being heated doesn’t mean “constantly heated,” but for this use, we obviously rely on the peak heating load…
As mentioned, the heating load calculation resulted in 2800 watts for 30 m² (323 ft²). However, that corresponds to less than half of the 300–350 watts per m² (28–33 watts per ft²) you indicated… which is correct?
We have trench heaters installed along the glass areas, but why do so many planners actually recommend underfloor heating for conservatories?
Thank you very much for the link. The conservatory has been standing for several years now, and I can only confirm your experience. There is definitely something special about sitting at the coffee table in a T-shirt while people outside trudge through the snow in heavy winter coats at -10°/-15°C (14°F/5°F)...
But precisely for the situations you described (Easter, Christmas, New Year’s Eve, birthdays), we want the assurance of being able to use the conservatory regardless of sunlight. Being heated doesn’t mean “constantly heated,” but for this use, we obviously rely on the peak heating load…
As mentioned, the heating load calculation resulted in 2800 watts for 30 m² (323 ft²). However, that corresponds to less than half of the 300–350 watts per m² (28–33 watts per ft²) you indicated… which is correct?
We have trench heaters installed along the glass areas, but why do so many planners actually recommend underfloor heating for conservatories?
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