For most houses in a built-up area, a small wind turbine for your home is not worth it. On an average roof between houses the yield is bitterly disappointing, often just 50 to 300 kWh a year, while the brochure promises 1,000 to 3,000 kWh. You usually never earn a turbine like that back within its lifespan. It is worth it if you live in open countryside or on the coast, have a free, open location, and can put up a real mast of 15 metres or higher. Then it gets interesting, and in winter sometimes even better than solar panels.
I’m Fred. I get this question a lot, usually from people who have just seen a video of a cute little windmill on a shed roof. In this article I explain, plainly, how it really works. With figures, with the physics behind it, and without talking you into anything.
Why is the yield of a small wind turbine so disappointing?
Here is the whole story in one sentence: wind power grows with the cube of the wind speed.
That sounds technical, but the effect is enormous. Double the wind speed and you don’t get twice the power, you get eight times as much. If it blows half as hard, you’re left with just an eighth.
And low down near the ground, between houses, trees and fences, it almost always blows softly and messily.
A few numbers to make this concrete. Manufacturers test their turbines at a clean, constant wind speed of often 11 or 12 m/s. On an ordinary roof in a built-up area you’ll average more like 3 to 4 m/s, and even then it’s turbulent (shifting from all directions). Because of that cube, this difference doesn’t mean “a bit less”, it means a fraction of the promised yield.
That’s why in practice you see this gap:
| Turbine | Promise (brochure) | Real yield (low, built-up) |
|---|---|---|
| Small roof turbine | ~800-1,000 kWh/year | a few dozen to ~100 kWh/year |
| Cheap online turbine | ~800 kWh/year | a few dozen kWh/year |
| Larger roof/garden turbine | 1,500-3,000 kWh/year | ~150-300 kWh/year |
These numbers aren’t guesswork. In a multi-year field test by the Dutch province of Zeeland, small turbines consistently delivered a fraction of the brochure promise: a model that was supposed to make 1,500 kWh a year came out at around 262 kWh in practice, and the smallest models got stuck at a few dozen kWh a year. These aren’t exceptions. This is the rule for small turbines mounted low in a built-up area. So remember: a rating of “1,000 watts” on the box tells you almost nothing about what actually comes out of the socket per year.
Horizontal axis or vertical axis: HAWT vs VAWT
There are roughly two types, and sellers love to mix up the terms. Here’s the difference in plain language.
HAWT (horizontal axis, the classic windmill with blades)
This is the shape you know from big wind turbines, in miniature. The rotor spins on a horizontal axis and has to turn to face the wind. More efficient than vertical, but it doesn’t like shifting wind directions and turbulence. So it’s good on a tall, free mast, bad between the houses.
VAWT (vertical axis, like the “wind swirl” or Savonius/Darrieus)
This one spins on a vertical axis and catches wind from every direction. That makes it less sensitive to turbulence and usually quieter. The downside: it’s less efficient, so it pulls less out of the air than a good HAWT at the same wind speed.
The practical summary:
| HAWT (blades) | VAWT (swirl/vertical) | |
|---|---|---|
| Efficiency in clean wind | Higher | Lower |
| Coping with turbulence | Poor | Better |
| Noise | Often more | Often less |
| Ideal spot | Tall free mast, open land | Messy wind, near a roof |
Note: a VAWT copes better with turbulence, but “copes better with low yield” still means low yield. Vertical on a city roof doesn’t solve the ground-level problem (too little, too messy wind).
How much wind do you need, and do you actually have it?
The rule of thumb from the industry: you need an average wind speed of at least 5 to 5.5 m/s at hub height before a turbine starts spinning usefully.
Where do you get that?
- Coast and immediate hinterland (North Sea coast, coastal regions, islands): here it blows hard enough. These are the “red zones” on the meteorological wind map.
- Open countryside elsewhere: possible, provided it’s genuinely free and with a tall mast.
- Inland, built-up area, between houses: almost never. Too little wind, too much turbulence.
Hub height matters at least as much as location. The higher up, the harder and steadier the wind. A turbine 2 metres above your shed roof sits in the “dirty” layer just above the buildings, exactly where the wind is worst. That same turbine on a 15-metre mast in an open field is a completely different machine in terms of yield.
That’s the crux of why a roof turbine almost always disappoints and a free-standing mast in a field sometimes does work.
What does a small wind turbine for your home cost?
Big spread, because “small wind turbine” covers everything from a toy to a serious installation.
| Type | Price guide (incl. installation) | What it is |
|---|---|---|
| Mini roof/garden turbine (300-600 W) | €300 – €1,500 | Small, low, little yield |
| Larger turbine (1-6 kW) on a mast | €4,000 – €15,000 | More serious, mast needed |
| “Real” small windmill (15-30 m mast, 15-72 kW) | €25,000 – €70,000+ | Countryside, farm, business |
On top of those prices there are often costs sellers forget to mention: the inverter, the mast and foundation, the connection to your fuse box, and sometimes groundwork and a cable run.
An important misunderstanding: subsidy schemes only count under “small windmills on your own land” the category with a mast of 15 to 30 metres and 15 to 72 kW, good for 30,000 to 185,000 kWh a year. That’s a completely different beast from the little roof swirl for a few hundred euros. When you read online that small windmills “pay for themselves in 6 to 10 years”, that’s about that big category out in the countryside, not about your shed roof.
What is the real payback time?
Let’s do the sums with honest figures. Say electricity costs you €0.35 to €0.40 per kWh.
Roof turbine example (built-up area):
Turbine €4,000, real yield 100 kWh/year. That’s €35 to €40 a year in saved electricity. Payback time: about 100 years. The turbine lasts 20 years at most. So you never earn it back.
Serious turbine on a free mast (good location) example:
| Yield/year | Saving/year (€0.40) | Purchase | Rough payback time |
|---|---|---|---|
| 5,000 kWh | €2,000 | €15,000 | ~8.5 years |
| 3,000 kWh | €1,200 | €10,000 | ~9 years |
| 1,500 kWh | €600 | €7,000 | ~12 years |
Don’t forget maintenance in that table, reckon on about €200 a year, plus an inverter you replace after 10 to 15 years. Subtract that and the pretty pictures get more sober.
To put it bluntly: Delft University of Technology professor Gerard van Bussel, who studied small wind turbines extensively, calls the current generation an unattractive investment. The real cost per kWh of small turbines is often around 25 to 35 cents, and at poor, low-mounted locations well above what you now pay for electricity from the grid. Large offshore wind turbines sit at around 9 cents. Small is simply inefficient.
Do you need planning permission?
Almost always, yes. Rule of thumb: to put up a wind turbine you apply for planning permission from your local council.
What you need to know:
- The rules differ per council and region. The council can be stricter than the region, never more lenient.
- A mast in the countryside is more likely to be allowed than a turbine on a roof in a residential area.
- Many councils have maximum heights in their local plan. Exactly the height you need for good wind is often the stumbling block.
- Applications in built-up areas are regularly refused, over noise, appearance and nuisance.
So always call your council first before you buy anything. A turbine you’re not allowed to put up is an expensive ornament.
How much noise and vibration does it make?
More than people think, especially with HAWT models. A spinning small turbine can give a clearly audible hum or whistle, and continuously, for as long as it’s windy. It’s precisely that persistent character that often makes it more annoying than the noise level on paper suggests.
Two things that often go wrong:
- Noise. A humming or whistling turbine above your bedroom is grinding at night. Neighbours aren’t happy about it either.
- Vibration. A turbine you mount on your roof structure or facade transfers vibration into the house. You can hear it and feel it in the structure. A free-standing mast with its own foundation is far cleaner here.
VAWT models (vertical) are usually quieter in this respect than HAWT with blades.
Feeding back, export rates and the inverter
Your turbine produces variable current, your house and the grid want clean 230 V. There’s an inverter in between, just like with solar panels. Count that cost in, and know it doesn’t last forever.
On feeding back: the yield is highest when you use the electricity yourself, directly. What you feed back to the grid is worth less financially, especially now that export compensation schemes are being wound down and many people are on contracts with low feed-in rates.
In practice this means: the more of your wind power you use yourself at the moment of generation, the better the sums. A little wind turbine spinning hard at night while you sleep mostly feeds back cheaply to the grid. Not worth much, then.
Wind alongside solar panels and a home battery
Here lies the one genuinely strong argument for home wind, and most articles skip it.
Sun and wind complement each other over time:
- Sun peaks in summer and during the day.
- Wind blows harder precisely in winter, at night and in bad weather, exactly when your solar panels do little.
Lovely in theory: in the dark season when your panels deliver nothing, your turbine is spinning. But this only works if your turbine stands at that good location and genuinely catches enough wind. In the city it stays a nice idea with no yield.
A home battery improves the sums for both: you store what you generate and use it yourself later, instead of feeding back cheaply. That raises your self-consumption, and self-consumption is where the money is. But count the battery as a separate investment with its own payback time, it’s no free bonus.
Sober order of priorities if you’re serious about going green: insulate first, then solar panels, then possibly a battery, and only after that wind, and only if your location genuinely allows it.
Maintenance and lifespan
A turbine has moving parts, out in all weather, day and night. That demands maintenance, unlike a solar panel that you broadly leave alone.
What you should count on:
- About €200 a year in maintenance is a realistic assumption.
- Bearings, brushes and moving parts wear out.
- You often replace the inverter after 10 to 15 years.
- Technical lifespan of the turbine itself: around 20 years, provided it’s well maintained.
A turbine you maintain poorly breaks down sooner and can become dangerous in a storm. This is not a “hang it up and forget it”.
When is a small wind turbine for your home worth it after all?
Line up all the points and the picture is clear. It’s worth it if you can tick as many of these boxes as possible:
- You live on the coast or in open countryside (red zone on the wind map).
- You have a free, open location with no trees or houses slowing the wind.
- You can put up a real mast, 15 metres or higher, no roof mounting.
- You get planning permission through your council.
- You use a lot of electricity yourself at the moment it’s windy.
- You can make use of a subsidy or tax benefit for the larger category.
It’s not worth it if:
- You live in a residential area or city garden.
- You want to put the turbine on or just above your roof.
- You’re hoping for the yield in the brochure.
For most readers, and I’d rather say this honestly than let you throw away 4,000 euros, this means: do solar panels first. On an ordinary roof they deliver a far more reliable return than a small wind turbine. Wind is for the lucky few with plenty of space and plenty of wind.
Frequently asked questions
How many kWh does a small wind turbine for your home produce per year?
In a built-up area often just 50 to 300 kWh, despite promises of 1,000 kWh or more. On a free, tall mast in a windy region a more serious turbine can make 1,500 to 5,000 kWh. Location and hub height determine almost everything.
Can I just put a wind turbine in my garden?
No, you usually need planning permission from the council. The rules differ per council and region, and in residential areas applications are regularly refused. Always check before you buy.
Is a wind turbine or solar panels better for the home?
For almost every house, solar panels are the better choice: more reliable return, no moving parts, less maintenance and easier to get permitted. Wind is only interesting as a supplement, at a genuinely windy, open location.
Why does my little wind turbine produce so much less than promised?
Because wind power grows with the cube of the wind speed. Low near the ground and between buildings it blows softly and turbulently, and then only a fraction of the promised yield remains. The brochure tests at ideal, constant wind you’ll never reach at home.
What is the payback time of a small wind turbine?
For a roof turbine in the city, often so long that you never earn it back within its 20-year lifespan. For a good turbine on a free mast in a windy region, 8 to 12 years is realistic, including maintenance and a new inverter along the way.
Does a vertical (VAWT) turbine make less noise than a normal one?
Usually yes. Vertical-axis turbines like the wind swirl are generally quieter and cope better with turbulent wind. But they’re less efficient, so you trade noise for yield. At a poor location even a quiet turbine won’t get you electricity.
Want to genuinely cut your energy bill, in the right order and without expensive missteps? Start at the basics. In my energy-saving guide at energie-verpulveraar.fredsbouwtekeningen.nl I show step by step where your money evaporates and which measures really do pay for themselves. That way you know exactly when wind is smart, and when you’re better off spending your cash on something else.