Aluminium is low-maintenance and lets in more light. Wood looks warmer and insulates better, but wants upkeep. Which frame fits you.
Greenhouse Type
Quick answer: Aluminium frames are low-maintenance, do not rot, and use slim glazing bars that let in more light, which is why nearly every kit and most premium glasshouses (Hartley, Alitex) use them. Wood frames, cedar at the premium end and pressure-treated softwood like Yoderbilt's southern yellow pine in the mid-market, look warmer, insulate a little better because wood does not conduct heat the way metal does, and feel more substantial, but they want periodic treating and cost more. Choose aluminium for zero upkeep, maximum light, and lower cost. Choose wood for looks, slightly better heat retention, and a more solid feel, if you accept the maintenance. It is a looks-and-upkeep decision, not a quality one.
Best for
Buyers weighing frame material before they shop brands, who want the maintenance and light tradeoffs named plainly.
Wrong fit
Buyers who have chosen a brand that only offers one frame material. Skip to the brand review.
Tradeoff
Aluminium is maintenance-free, cheaper, and lets in more light. Wood looks warmer, insulates a touch better, and feels more solid, but you sign up for periodic upkeep and a higher price.
Aluminium frames are maintenance-free, do not rot, and use slim bars that let in more light. Wood frames look warmer, hold heat a little better, and feel more substantial, but they want treating and cost more. That is the whole decision, and neither is a quality problem, it is a looks-and-upkeep choice. Both build greenhouses that last for decades when they are made and maintained well.
We don't sell greenhouses. We save you from buying the wrong one, and the frame is where buyers pick with their eyes and regret it later, either signing up for wood maintenance they did not want or buying aluminium they find cold-looking. This page names the real tradeoffs so you choose with your eyes open.
The frame is one of two type decisions, the other being glazing, so read this next to glass vs polycarbonate. Settle both and your brand shortlist writes itself, from best greenhouses.
Quick Answer: Aluminium vs Wood at a Glance
Dimension
Aluminium
Wood (cedar / softwood)
Maintenance
None, does not rot or need painting
Periodic treating or oiling
Light
More, slim glazing bars
Less, thicker bars cast more shade
Insulation
Conducts heat, slightly worse at the bars
Wood does not conduct, holds heat a touch better
Look
Modern, utilitarian (or powder-coated)
Warm, traditional, substantial
Cost
Lower, most kits
Higher, cedar is premium
Weight
Light, easy to handle
Heavier, more solid feel
Lifespan
Decades, no rot
Decades if maintained, cedar resists rot naturally
Both frame types appear across the market, and premium exists in both, hand-built aluminium (Hartley, Alitex) and premium cedar makers. Verify a specific model's bar profile and finish at write time.
Aluminium: Low Maintenance and More Light
Aluminium is the default for good reasons, and they are practical ones. It does not rot, rust, or need painting, so it is genuinely maintenance-free, you build it and forget it. Its strength lets the glazing bars be slim, which means less shading and more light reaching your plants, a real growing advantage. It is light to handle during assembly, and modern powder-coating means it no longer has to look like raw metal, you can get it in black, green, or heritage colors that read far warmer than old mill-finish aluminium.
The fit statement: for the buyer who wants maximum light, zero upkeep, and the lowest cost, aluminium is the obvious and correct choice, which is why nearly every kit and both top premium glasshouse makers use it. The honest caveats: bare aluminium conducts heat, so the frame bars lose a little more warmth than wood does (a minor effect on the whole greenhouse), and a plain aluminium kit can feel utilitarian next to timber. Neither is a dealbreaker for most buyers, and the light and maintenance advantages usually win.
Wood: Warmth, Heat Retention, and Upkeep
Wood is the choice for looks and feel, and it has two genuine performance points too. First, wood does not conduct heat the way metal does, so a timber frame holds warmth a little better, a small but real edge for cold-climate season extension. Second, a wood frame simply feels more substantial and looks warmer and more traditional in a garden, which is why a lot of buyers want it. There are two lanes: premium cedar, which is naturally rot-resistant and ages beautifully, and mid-market pressure-treated softwood like Yoderbilt's southern yellow pine, which is treated to resist rot at a lower price.
The fit statement: for the buyer who wants a warm, solid, traditional-looking greenhouse and does not mind a bit of care, wood is a lovely choice, and cedar in particular is heirloom-grade. The honest caveat is maintenance, wood wants periodic treating, oiling, or painting to keep it sound and looking right, and if you skip it, softwood especially can rot over years. It also casts a bit more shade through thicker bars and costs more than aluminium. If you accept the upkeep, none of that is a problem. If you want to never touch the frame again, aluminium is your answer.
Insulation and Light: The Real Performance Difference
These two properties pull in opposite directions, which is the heart of the choice. Wood insulates slightly better because it does not conduct heat, so a timber house holds warmth marginally longer on a cold night. But aluminium lets in more light because its bars are slimmer, so an aluminium house is brighter, which matters for winter growing when light is scarce. For most buyers both effects are modest next to the glazing choice, which controls far more of the heating and light picture than the frame does. If winter heat retention is your priority, that is a glazing decision first (twin or triple-wall polycarbonate), covered in glass vs polycarbonate, and a frame decision a distant second.
Cost: Aluminium Lower, Cedar Premium
Aluminium is the cheaper frame and dominates the value lane, so a Palram/Canopia at $1,500 to $6,000 is aluminium, and so is a bespoke Hartley at the top, aluminium spans the whole price range. Wood splits: pressure-treated softwood like Yoderbilt's is mid-market and competes on price with a solid build and a warm look, while premium cedar frames are a genuine luxury spend, closer to glasshouse money, bought for the looks and the heirloom quality. So "wood costs more" is true at the cedar end and less true for treated softwood. Match the frame to your budget and your appetite for upkeep, and remember the frame is one line among several, the base, anchoring, and ventilation are the same job regardless, from the real cost of a greenhouse.
Which Frame Fits You
Choose aluminium if you want zero maintenance, the most light for winter growing, the lowest cost, and you are fine with a modern or powder-coated look. This is the right call for most buyers, from a mid-market Palram/Canopia to a premium Hartley or Alitex.
Choose wood if you want a warm, traditional, substantial-looking greenhouse and slightly better heat retention, and you accept periodic treating. Pressure-treated softwood like a Yoderbilt is the mid-market pick, premium cedar the heirloom one.
Remember the frame is the second decision, not the first. Glazing controls more of your light and heating than the frame does, so settle glass vs polycarbonate alongside this. And if your real goal is a warm room to sit and work in, no frame material makes a greenhouse into that, an office pod is built for people and heat, weighed at backyardoffice.guide.
Frequently Asked Questions
Is an aluminium or wood greenhouse frame better?
Neither is better outright, it is a looks-and-upkeep choice. Aluminium is maintenance-free, does not rot, lets in more light through slim bars, and costs less, which is why most kits and top glasshouses use it. Wood looks warmer, feels more solid, and holds heat a touch better, but wants periodic treating and costs more, cedar especially. Choose aluminium for no upkeep and maximum light, wood for looks and feel if you accept the maintenance.
Does a wood greenhouse frame rot?
Softwood can over years if you do not maintain it, which is the main caveat with a wood frame. Pressure-treated softwood like southern yellow pine resists rot and lasts well with periodic treating, and cedar is naturally rot-resistant and ages beautifully with minimal care. The key is upkeep: a treated or oiled wood frame lasts decades, a neglected softwood one does not. If you will not maintain it, aluminium removes the risk entirely.
Do aluminium frames make a greenhouse colder?
Marginally, and less than most buyers fear. Aluminium conducts heat, so the frame bars lose a little more warmth than wood, but the effect on the whole greenhouse is small next to the glazing, which controls most of the heat loss. A twin-wall polycarbonate house on an aluminium frame holds heat far better than a single-glass wood one, because glazing matters more than frame material for temperature. If winter warmth is the priority, choose the glazing first.
Why do premium glasshouses use aluminium instead of wood?
Because hand-built aluminium delivers the strength, the slim sightlines, and the maintenance-free life that premium buyers want, at heirloom quality. Hartley Botanic and Alitex both build in aluminium precisely because it does not rot, holds fine tolerances for large glass panes, and needs no ongoing treatment, while powder-coating gives it a warm finish. Premium wood exists too, in cedar glasshouses, but the top aluminium makers show that aluminium is not just the cheap option, it spans the whole range.
Does a wood frame block more light than aluminium?
A little, yes. Wood is not as strong as aluminium, so its glazing bars have to be thicker to carry the same load, and thicker bars cast more shade inside. Aluminium's slim bars let in more light, which is a real advantage for winter growing when light is already scarce. The difference is modest for most gardeners, but if you are growing through dark northern winters and want every bit of light, aluminium has the edge here.
Which frame is best for a cold climate?
Look at glazing before frame, because it matters far more for warmth. Between the frames, wood holds heat marginally better since it does not conduct like metal, so a cedar or treated-softwood house has a slight edge in a cold climate. But a well-insulated twin or triple-wall polycarbonate glazing does far more for your heating bill than the frame material does. For a hard winter, prioritize the glazing (see glass vs polycarbonate), then pick the frame on looks and upkeep.
Methodology
These guides are built from manufacturer documentation, public specifications, primary research where health claims matter, and repeated buyer questions that show up in real ownership and installation decisions.
Manufacturer responses can clarify pricing bands, warranty terms, support footprint, or common mistakes. They do not move a page up the shortlist on their own.
