# Solar Panels for Bungalows and GCBs in Singapore

A Good Class Bungalow's roof area supports far more than a terrace or semi-detached home, commonly 30 to 120 kWp. Here is how sizing actually works once a roof this large is in play.

**Quick answer:** A standard bungalow typically supports 15 to 20 kWp; a Good Class Bungalow (GCB), with far more roof area, commonly supports 30 to 120 kWp depending on the property. Sunnify's online estimate applies a conservative base cap for large properties; a real site survey determines the actual achievable size.

A Good Class Bungalow's roof area genuinely puts it in an entirely different sizing category from a terrace or semi-detached home. Where those smaller property types typically support somewhere in the 8 to 15 kWp range, a GCB commonly supports 30 to 120 kWp instead, simply because there is substantially more genuinely usable roof area available to design a system around from the outset.

## Why is the achievable system size so much larger for a GCB?

System size scales directly with usable roof area, roughly 5 to 6 square metres per kWp, and a Good Class Bungalow's plot size and roof footprint are, by definition under Singapore's own planning guidelines, significantly and consistently larger than those of a standard landed home. A GCB with a genuinely large single-storey footprint or multiple distinct roof sections can support a system many times the size of a typical, standard terrace house installation entirely, before even considering ground-mount options on unused land, covered in [ground-mount solar for landed homes with extra land](/blog/ground-mount-solar-landed-homes-singapore). Roof shape matters here more than at any other property type: a GCB with one large, simple roof plane can lay out panels far more efficiently per square metre than one with the same total area split across several smaller, oddly angled sections, which is part of why the 30-120kWp range is so wide even before mature-tree shading, common on larger, more established plots, is factored in.

## Why does the free online estimate show a smaller number?

The Sunnify online estimate applies an 8 kWp base cap for large landed properties (the other landed property type category) as a deliberately conservative default. This exists because satellite-based estimation, while a useful starting point, cannot reliably judge every GCB roof's specific shape, shading from mature trees common on larger plots, or the electrical supply capacity available. A proper site survey replaces this conservative estimate with a real, roof-specific figure once someone actually measures the property.

This gap between the tool's conservative default and a property's true potential tends to be far larger for GCBs than for any other property type, precisely because the base cap was never designed with a genuinely GCB-scale roof specifically in mind when it was first set as a conservative default value.

| Property type | Typical system size |
| --- | --- |
| Terrace house | 10 to 15 kWp |
| Semi-detached (one roof half) | 8 to 12 kWp |
| Standard bungalow | 15 to 20 kWp |
| Good Class Bungalow (GCB) | 30 to 120 kWp, roof-dependent |

## What do real bungalow-scale installations actually look like?

Two documented Sunnify installations show how much variation exists even within bungalow-scale systems. A [documented installation at Mount Sinai](/projects) is a 20.6kWp system across 42 panels on a pitched detached roof, currently saving the household roughly S$6,400 a year. A [documented installation at Berwick Drive](/projects) reaches 26.4kWp across 54 panels split over two separate flat-roof sections, the largest documented residential system in Sunnify's own portfolio.

The gap between these two real numbers, and the far larger 30-120kWp range quoted for GCBs generally, illustrates the same point made throughout this guide: a bungalow or GCB label describes a broad category, not a specific number, and the only way to know where a specific roof actually lands is to have it properly surveyed.

Both real systems also sit well below the top of the 120kWp theoretical range, which is itself instructive: even a genuinely large, well-documented GCB installation often lands in the 20-30kWp band once actual roof geometry, obstructions, and design choices are accounted for, rather than automatically reaching for the upper bound the property type alone might suggest is possible.

## How does a multi-section roof change the design, not just the size?

Beyond simply adding more capacity, a roof split across multiple distinct sections, as at Berwick Drive, often needs a more deliberate electrical design than a single continuous roof face. Different sections may face different orientations or receive different shading through the day, which affects how strings of panels are grouped and which inverter configuration captures the most generation from each section independently, rather than letting a weaker section drag down a stronger one. This is the same underlying principle covered in Sunnify's guide to [inverter sizing](/blog/solar-inverter-sizing-clipping-singapore), applied at a larger scale: a GCB-sized system with multiple roof sections often benefits from multiple independent inverter inputs or microinverters, so that shading or orientation differences on one section don't cap the output of sections that would otherwise be performing well.

## Does electrical supply still cap a GCB system the same way?

Yes, in principle, but GCBs are far more likely to already have or qualify for three-phase electrical supply given their larger overall electrical loads, which removes the roughly 10 to 13 kWp single-phase ceiling that constrains smaller landed homes. Confirming the property's existing phase supply, or the cost to upgrade it, remains a necessary step before finalising a large system's design. A GCB genuinely considering the upper end of the 30-120kWp range without existing three-phase supply should treat that confirmation as one of the very first steps, not a detail to sort out after a system size has already been agreed with an installer.

## Does a GCB's conservation status ever require extra approval for solar?

Sometimes, and it's worth checking specifically rather than assuming the standard process applies. Most Singapore landed homes don't need URA planning permission for solar at all, but GCB Areas are themselves specially designated by URA, and some individual GCBs, black-and-white bungalows in particular, carry additional heritage or conservation guidelines that can require URA approval before installation, specifically to manage visual impact on the roofscape.

Where this applies, installing solar panels without any other structural work is generally treated as a lighter-touch category of conservation work rather than a major redevelopment application, so it isn't necessarily a slow or difficult process, but it is a genuinely separate step a standard terrace or semi-detached installation never encounters. Confirming your specific property's conservation status with URA, or asking your installer to check, is worth doing before finalising a design and timeline. An installer with genuine experience on GCB-scale projects should already know how to handle this specific step, which is itself a useful signal when comparing quotes from installers with different levels of experience at this property scale.

## What should a GCB owner actually do before requesting quotes?

Treat the online estimate as a conservative starting reference point only, not the real ceiling, and request a proper, full site survey as early in the process as possible, since the gap between the calculator's conservative default and a GCB's actual achievable size can be substantial. A larger system also makes the [total cost of ownership](/blog/solar-total-cost-of-ownership-singapore) math even more favourable, since fixed costs are spread across significantly more generation capacity. At GCB scale, this also means the absolute dollar gap between a well-designed system and a poorly-designed one, say, one that ignores multi-section shading or under-specifies the inverter configuration, is considerably larger than the equivalent gap on a terrace-scale system, which makes getting the design right upfront worth real scrutiny rather than defaulting to whichever quote arrives first.

Run the [Sunnify solar estimate](/solar-estimate-singapore) as a starting point, then book a [site review](/site-review) to get the real achievable system size for a specific GCB roof.

## Frequently Asked Questions

### How big a solar system can a GCB roof in Singapore actually support?

It depends entirely on the specific roof, but GCB systems commonly run 30 to 120 kWp given the much larger roof area typical of Good Class Bungalow properties compared to terrace or semi-detached homes. A site survey with satellite or on-site roof measurement is the only way to confirm the real figure for a specific property.

### Why does the online solar calculator show a smaller number than what a GCB roof could actually support?

Think of the online figure as a floor, not a forecast, deliberately set low because satellite imagery alone can't distinguish a heavily shaded, oddly shaped GCB roof from an ideal one at a glance. It's built to never overpromise across the full range of large landed properties it needs to cover, which means it's specifically expected to undershoot on a genuinely generous roof rather than get it exactly right for every property.

### Does a bigger GCB solar system cost proportionally more?

Roughly, though cost per kWp tends to improve slightly at larger scale, since fixed costs like permits, scaffolding, and grid connection work are spread across more capacity. A 60 kWp GCB system typically costs somewhat less per kWp than a 15 kWp bungalow system, even though the total installed cost is naturally much higher, and the gap widens further at the very largest end of the range where economies of scale genuinely compound rather than simply repeating.