Exact direction
North-east, north, and north-west are not the same orientation. The actual azimuth should be considered rather than applying one blanket rule to an entire half of the compass.
Solar roof questions answered
Are north-facing solar panels worth installing?
One installer says never put solar panels on a north-facing roof. Another wants to use every available roof section.
Neither rule is good enough on its own. A north-facing roof should be judged by what it can actually produce, what the extra panels cost and whether the household can use the energy.
The short answer
Yes — north-facing solar panels can be worth installing, but not on every roof and not at any price.
Roof direction matters because it changes how much solar energy reaches the panels across the year.
A south-facing roof generally has a natural advantage in the UK, but that does not make every other orientation unsuitable.
The useful question is:
What will these particular panels produce on this particular roof?
Then compare that generation with the additional cost and the household's ability to use it.
What determines the answer?
“North-facing” is only one part of the calculation.
Roof pitch
A shallow roof and a steep roof expose the panels to daylight differently. Pitch can therefore make a major difference to the usefulness of a northerly orientation.
Shading
Trees, neighbouring buildings, chimneys and roof features can matter just as much as compass direction.
Installation cost
Additional panels may be relatively inexpensive when they are being fitted as part of a larger installation, but expensive structural or electrical complications can change the calculation.
Household demand
Extra generation has more value when the household can use, store or beneficially export it.
System design
String design, MPPT allocation, inverter sizing and other roof orientations can influence whether adding another roof section makes technical sense.
Not all north is equal
North-east and north-west can be very different from due north.
Homeowners are often told that any roof containing the word “north” should be ignored.
That is too crude.
NE
Can receive useful morning solar exposure.
N
Usually the least favourable of the main orientations.
NW
Can receive useful later-day solar exposure.
Pitch
Can materially alter all three outcomes.
A roof that is only slightly north of east or west should not be treated in the same way as a steep roof pointing directly north.
Roof pitch matters
The steeper the roof, the more important its direction can become.
Imagine two roofs that both point north.
One is shallow. The other is steep.
Although the compass direction is identical, the angle at which those panels see the sky is very different.
That can produce significantly different annual generation.
Orientation and pitch should always be assessed together.
“North-facing” by itself is not enough information to judge a roof.
Scottish conditions
Solar panels do not stop working because the sky is cloudy.
Solar panels generate electricity from daylight, not only from bright direct sunshine.
Scotland has long summer daylight hours and also many periods of diffuse light under cloud.
That does not remove the disadvantage of a poor orientation, but it is one reason why the real answer should come from a generation estimate rather than a simple compass rule.
A north-facing Scottish roof may still generate useful electricity across the year.
The question is whether the predicted amount is enough to justify using that roof space.
When north-facing panels can make sense
There are several situations where using a northerly roof may be perfectly reasonable.
- The better-facing roof areas are already full.
- The north-facing roof has a relatively favourable pitch.
- The orientation is north-east or north-west rather than due north.
- There is little or no shading.
- Additional panel installation cost is relatively modest.
- The household has high electricity demand.
- There is a battery capable of using some additional generation.
- An EV or heat pump creates useful additional demand.
- The predicted annual generation still provides acceptable value.
None of these points proves that north-facing panels should be fitted.
They explain why automatically rejecting them can also be a mistake.
When they may not make sense
Some north-facing roof sections simply do not justify the extra panels.
A particularly steep due-north roof with significant shading may offer relatively poor annual generation.
If using that roof also requires extra scaffolding, complex cabling, additional optimisers or other costly work, the economics can weaken further.
The household may also have little need for the extra generation.
More panels are not automatically a better solar system.
The extra roof area should earn its place in the design.
East-west-north combinations
A multi-orientation array can sometimes produce a broader generation profile across the day.
A solar system does not have to consist of one single roof face.
Some properties may use combinations of east, west, south, north-east or north-west roof areas.
These sections produce electricity at different times and at different levels.
That can sometimes create a wider generation profile rather than concentrating most production around one period of the day.
But the inverter must also be able to deal sensibly with the different strings and orientations.
This is where MPPT availability and inverter design become important.
Batteries
A battery can make solar generation more useful — but it cannot make a poor roof generate more electricity.
If additional north-facing panels create surplus electricity at times when the house does not need it, a battery may store some of that generation for later.
That can improve self-consumption.
But a battery does not change the physical generation potential of the roof.
First estimate the generation. Then decide what to do with it.
Do not use a battery to disguise weak solar design.
For more detail, see What Size Solar Battery Do I Actually Need?
Panel count
Filling every roof is not the same thing as designing the right system.
A quotation may look impressive because it contains more panels than a competing proposal.
But panel count by itself says very little.
Fifteen well-positioned panels may be more useful than twenty panels spread across poor roof sections.
Equally, twenty panels may be the better design where the additional roof sections still produce useful electricity and the household has sufficient demand.
The number should follow the design.
Inverter design
Multiple roof directions also have to make electrical sense.
Panels on different orientations may need to be separated into appropriate strings and MPPT inputs.
That means the inverter choice can affect whether a complicated roof layout works properly.
An installer should be able to explain:
- How the panels are divided into strings
- Which roof section is connected to each MPPT
- Whether string voltages remain within operating limits
- Whether different orientations have been mixed appropriately
- Why the chosen inverter suits the full array
Three roof examples
“North-facing” can describe three completely different opportunities.
Shallow north-east roof
Little shading, useful roof area and a modest pitch. This may deserve serious consideration rather than automatic rejection.
Steep due-north roof
A much more challenging orientation where predicted generation needs to justify the extra installation cost.
North-west roof with high household demand
Additional later-day generation may still be valuable where the house has substantial electricity demand and better roof areas are already fully used.
Questions to ask the installer
Make them explain the north-facing panels rather than simply adding them to increase system size.
- What exact direction does this roof face?
- What is the roof pitch?
- What annual generation is predicted from this roof alone?
- How does that compare with the better-facing roof sections?
- Is there any significant shading?
- What additional cost is associated with using this roof?
- How will the panels be divided between inverter MPPTs?
- How much of the extra generation is expected to be self-consumed?
- How much may be stored in the battery?
- How much may be exported?
- What happens to the proposal if these panels are removed?
If the installer cannot show why the additional roof area makes sense, the panel count alone is not a justification.
Common questions
Quick answers.
Are north-facing solar panels worth installing?
They can be. They normally produce less electricity than well-positioned south-facing panels, but roof pitch, exact orientation, shading, cost and household demand can still make them worthwhile.
Should I avoid north-facing solar panels completely?
No. The roof should be assessed rather than rejected automatically. North-east and north-west roofs in particular can sometimes provide useful generation.
Does roof pitch matter?
Yes. Two roofs pointing in exactly the same direction can perform differently if their pitches are different.
Are north-east and north-west better than due north?
Generally they have more favourable solar exposure than a roof pointing directly north, although pitch and shading still matter.
Can north-facing panels work in Scotland?
Yes. Panels generate from daylight as well as direct sunshine. The sensible approach is to calculate expected annual generation for the actual Scottish property.
Should I use the north roof after filling the south roof?
Potentially. If additional generation still has useful value and the north-facing roof performs reasonably, using extra roof space can make sense.
Does a battery make north-facing panels worthwhile?
A battery can help use the electricity at a different time, but it cannot increase the amount of electricity produced by the panels.
How should a north-facing roof be assessed?
Consider exact direction, pitch, shading, usable roof area, predicted generation, additional installation cost, household demand, tariffs and the complete system design.
Related Tom Solar guides
Roof direction is only one part of a solar design.
Measure the roof before judging it
Do not accept “north-facing” as either an automatic yes or an automatic no.
Tom Solar looks at the actual direction, roof pitch, shading, usable space, generation potential, household demand and wider system design before deciding which roof sections are worth using.