The quick answer
There is no single price for “solar for a house”. Cost follows the specification, and the specification follows your load.
The five things that move the number: daily energy use, backup hours required, whether you run air conditioning, roof and site conditions, and battery chemistry.
Backup hours are usually the biggest single lever — asking for 24 hours instead of 8 changes the battery cost dramatically.
Two quotes are only comparable if they specify the same array, inverter rating and usable storage. Compare specifications, not headline totals.
Get an indicative size first with the system finder, then ask for a price against that exact specification.
Why quotes vary so much
Ask three installers to price “solar for a four-bedroom house” and you will get three very different numbers. That is not necessarily dishonesty — it usually means they have quoted three different systems.
One may have assumed you want lighting and refrigeration through the night. Another may have assumed the air conditioning runs. A third may have quoted a bank that only carries you until midnight. Until the specification is fixed, the prices are not comparable at all.
This is why Sunnovate quotes against a written specification produced after a site assessment, rather than a package name.
The five factors that decide your price
1. Daily energy consumption
How much energy you use in a day sets how big the array must be to replace it. More consumption means more panels and a larger inverter.
2. Backup hours required
This is usually the largest single lever, and the one clients most often underestimate. Storage scales with the hours you want covered. Moving from eight hours to a full day is not a small increment.
3. Air conditioning
Cooling is typically the heaviest continuous load in a Nigerian home. A single inverter AC unit can roughly double a household’s daily energy on its own, which affects array, inverter and battery simultaneously. It must be declared at sizing stage.
4. Roof and site conditions
Roof orientation, shading, structure and cable runs all affect what can be installed and how much labour and mounting hardware the job needs. This is why a satellite image is not enough to design from.
5. Battery chemistry
Lithium costs more up front than tubular but delivers more usable capacity per unit of rating. See our lithium vs tubular comparison for the trade-off in detail.
How to compare quotes properly
Put the quotes side by side and check that each one states:
Array size in kWp, and the module wattage and count.
Inverter rating, and whether it has surge headroom for your heaviest motor.
Storage capacity, and critically whether the figure quoted is rated or usable.
What is included — mounting, protection, cabling, labour, commissioning.
How many hours of backup the design is actually intended to deliver.
If a quote does not state those, you cannot compare it with one that does. A cheaper number against a smaller specification is not a better deal.
Where it is sensible to save — and where it is not
Reasonable savings: starting with a system that covers your essential loads and expanding later, provided the inverter was specified with headroom. Choosing tubular if the bank will only be cycled occasionally. Phasing a commercial installation.
False economies: undersizing the inverter so it trips under your fridge or pump. Buying storage that cannot carry you to morning. Skipping the site assessment. Buying components separately that were never checked for compatibility.
Almost every system we are called out to repair was not sold the wrong equipment. It was sized against a budget rather than against a load.
Getting a price you can rely on
Run the system finder for an indicative array, inverter and storage size. Then request a quote. An engineer confirms the design on site, and you receive a price for that exact specification — set out so you can compare it against anyone else’s.
If a smaller system covers what you actually need, we will say so.
Questions worth asking any installer
Before you accept any quote — ours included — these questions separate a specification from a sales pitch.
1
“How many hours of backup is this designed to deliver, and at what load?” If the answer is vague, the storage was not sized against anything.
2
“Is the battery figure rated or usable capacity?” These are materially different numbers, and quoting the rated figure makes a bank look larger than it is.
3
“What is the surge headroom on this inverter, and what is my largest motor load?” If they have not asked about your pump or fridge, they have not sized for it.
4
“Did you measure the roof, or estimate it?” Orientation, shading and structure decide what can actually be installed.
5
“What is included — mounting, protection, cabling, labour, commissioning?” A total that excludes these is not comparable with one that includes them.
6
“What happens if my demand grows?” Headroom specified now is far cheaper than a replacement inverter later.
Why the cheapest quote is often the most expensive
An undersized system does not fail immediately. It fails gradually and expensively: the bank is cycled too deeply and ages early, the inverter trips under load, and the array never fully recharges what was drawn overnight. The replacement cost arrives two years later, on top of what was already spent.
Comparing specifications rather than totals is the single most useful thing a buyer can do.
Get an indicative size before you get a price
Knowing roughly what you need makes every quote you receive easier to compare — and much harder to inflate.
Frequently asked questions
It depends entirely on the specification, which depends on your load and required backup hours. The same property can need very different systems. Run the system finder for an indicative size, then request a quote priced against that exact specification.
Because storage scales directly with the hours of backup you ask for, and because usable capacity is a fraction of rated capacity. Asking for a full day of autonomy rather than a night changes the bank size substantially.
Many clients start with a system covering essential loads and expand later. That works well if the inverter and configuration were specified with expansion in mind, so tell us at design stage.
It reduces what you draw from the grid and, with adequate storage, what you spend on generator fuel. How much depends on your consumption and system size, which is why we model it against your own bills during the assessment rather than publishing an average.
Tell us about the property when you enquire and we will confirm what the assessment involves for your situation before anything is scheduled.
Watch for whether mounting hardware, protection, cabling, labour and commissioning are itemised. A quote missing those is not comparable with one that includes them.
