Garden Dome vs Sunroom: Standalone Light vs Built-On Glass
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Quick answer
A sunroom adds a glazed room onto the house at conservatory-level cost and disruption; a garden dome gives you a light-filled space anywhere in the garden, from £899, built in an afternoon or a day. For light and value without a building project, the dome wins. For a permanent room physically joined to the house, a sunroom is the one.
Attached vs standalone
A sunroom (a glazed room attached to the house, a close cousin of the lean-to conservatory) and a garden dome both chase the same feeling: sitting in light, with the outdoors around you. The difference is that one is a building project joined to your home, and the other is a standalone structure you place in the garden.
A sunroom is built onto the house: foundations, dwarf walls, glazing, often planning and building regulations involvement, and the cost and weeks of work that come with any extension. It becomes part of the home's footprint, which is its main appeal.
A dome is standalone and placed wherever the light and view are best: no attachment to the house and no dug foundations, just a level, firm base. A garden structure of this size is usually permitted development, but check with your local planning authority, especially for a listed building, a conservation area, or siting and height near a boundary; rules differ in Scotland, Wales and Northern Ireland, and our planning permission guide covers the detail. Its individually numbered panels bolt together with nuts and bolts and no specialist tools, and most owners build it in an afternoon or a day. If you'd rather not, our Built for you installation service can build and anchor it for you. You're not extending the house; you're adding a beautiful room to the garden.
Side by side
| Sunroom | Garden dome | |
|---|---|---|
| Position | Attached to house | Anywhere in the garden |
| Cost | Extension-level, typically many thousands of pounds | From £899 |
| Build | Foundations, weeks of work | An afternoon or a day, on a level, firm base |
| Planning and building regulations | Often involved | Usually not needed, but check locally |
| Light | Good | Excellent: clear all round |
| Glazing | Glass | Solid, UV-protected polycarbonate (around 250 times the impact resistance of glass) |
| Adds to house footprint | Yes | No |
| Movable | No | Yes: it unbolts and can be rebuilt elsewhere |
| View | Towards the garden | Panoramic, immersive |
Where the dome leads
- Place it for the best light and view. A sunroom is fixed to one wall of the house; a dome goes wherever the sun falls and the outlook is finest: the bottom of the garden, beside the trees, facing the sunset.
- Cost and disruption. From £899 and an afternoon or a day of assembly, versus an extension's budget and weeks of building work.
- Immersion. A sunroom looks out from the house; a dome puts you in the middle of the garden, light and view all around.
- Flexibility. It bolts together, so if your plans change it can be taken down and rebuilt somewhere else.
Where a sunroom wins
To be fair: if you specifically want a room physically connected to the house (step from the kitchen straight into the glazed space, add to the home's floor area, and have a permanent, lockable, insulated extension), that's exactly what a sunroom is. A dome is a separate garden building, comfortable and beautiful but not joined to the house. Polycarbonate isn't an insulator, so on cold evenings you'll want a heater. The door doesn't lock as standard either, so it isn't the place to leave valuables overnight. If integration with the home is the goal, the sunroom is right.
The recommendation
Want light, a view and a lovely room without the cost and upheaval of an extension, and the freedom to site it anywhere? A dome, in Ultra, our pick for most gardens, including windy ones; the 3.5 m Standard in Ultra is a good place to start. Want a permanent glazed room joined to the house, and you've budget for a build? A sunroom. The dome gives most people the sunlit space they're picturing for a fraction of the outlay.
Frequently asked questions
What's the difference between a sunroom and a garden dome?
A sunroom is a glazed room built onto the house; a dome is a standalone garden structure you can place anywhere. The dome costs far less and needs no extension work; the sunroom joins to the home.
Does a dome cost less than a sunroom?
Yes, substantially. A GeoDomeX dome starts from £899, against conservatory-level cost for a sunroom, with no dug foundations or weeks of building work.
Does a dome attach to the house?
No. It's standalone, so you can site it wherever the light and view are best. A sunroom is fixed to the house.
Which has better light?
The dome, typically. Clear panels all round give panoramic daylight, where a sunroom looks out from one side of the house.
Which adds to my home's floor space?
A sunroom, because it's a built extension. A dome adds a separate room to the garden rather than to the house footprint.
Sources: polycarbonate material data from A&C Plastics, Piedmont Plastics and KASTLITE.