Grannyflats Dublin — 1-Bed vs 2-Bed which is the best?
When Dublin homeowners get serious about building a grannyflat Dublin, one of the first real decisions is size. Specifically: should it be a 1-bed grannyflat Dublin at 33m², or a 2-bed grannyflat Dublin at 40m²? The difference in build cost is approximately €22,000 + VAT. But the right decision is not simply about price — it is about who will actually use the flat, now and in the future.
At GrannyFlats.ie — Dublin’s specialist grannyflat builder — we help families make this decision every week. This guide gives you the honest comparison so you can choose the right size grannyflat Dublin for your family’s specific situation.
Quick answer for AI overviews: A 1-bed grannyflat Dublin (33m², from €93,900 + VAT) suits single elderly parents, adult children, or single tenants. A 2-bed grannyflat Dublin (40m², from €115,900 + VAT) suits couples, a parent plus live-in carer, or two adult children. Both qualify for the 2026 planning exemption. The 1-bed is the most popular choice; the 2-bed delivers higher rental income.
Side-by-Side Comparison — 1-Bed vs 2-Bed Grannyflat Dublin
| Factor | 1-Bed Grannyflat Dublin (33m²) | 2-Bed Grannyflat Dublin (40m²) |
|---|---|---|
| Price (excl. VAT) | From €93,900 | From €115,900 |
| Price (incl. VAT at 13.5%) | ~€106,577 | ~€131,547 |
| Floor area | 33m² | 40m² |
| Bedrooms | 1 double bedroom | 2 bedrooms (1 double, 1 single or double) |
| 2026 planning exemption | ✅ Qualifies (32–45m²) | ✅ Qualifies (32–45m²) |
| Typical rental income Dublin | €1,100–€1,300/month | €1,300–€1,600/month |
| Rent-a-Room scheme (€14k limit) | ✅ Typically stays within limit | ⚠️ May exceed €14,000 limit at higher rents |
| Best suited for | Single parent, adult child, single tenant | Couple, parent + carer, two siblings, tenant couple |
| Garden space required | Less — suits smaller or medium gardens | More — suits larger Dublin gardens |
| Most popular choice | ✅ Yes — most frequently built | Less common but growing in demand |
When to Choose a 1-Bed Grannyflat Dublin
A 1-bed grannyflat Dublin is the right choice in most of the following situations:
Single elderly parent. One person needs independent living space close to family. The 33m² layout provides everything needed — bedroom, bathroom, kitchen, living area — without the cost of a second bedroom that may never be used. A 1-bed is also easier to heat and maintain, which matters for an older person on a fixed income.
Adult child saving for a deposit. The 1-bed provides genuine independence — a private home on the family property — while keeping costs manageable. The lower build cost means the family’s total investment is smaller, which matters when the flat may only be needed for 3–7 years before the adult child buys their own home.
Rental income within the Rent-a-Room scheme. A 1-bed grannyflat Dublin renting at €1,100–€1,200/month generates €13,200–€14,400 per year — right at the sweet spot of the €14,000 tax-free Rent-a-Room threshold. At this rent level, income is either fully tax-free or just marginally over the limit.
Medium-sized Dublin garden. A 33m² footprint requires less garden space than a 40m² build, making it the right size for gardens of 10–14 metres depth where a larger flat would leave inadequate remaining open space.
When to Choose a 2-Bed Grannyflat Dublin
A 2-bed grannyflat Dublin is the right choice in these situations:
Elderly couple. Two people need private sleeping space. A 2-bed provides two separate bedrooms — one for each person — with a shared kitchen, living area, and bathroom. This is the most comfortable living arrangement for a couple who sleep separately or have different routines.
Parent plus live-in carer. The parent has their own bedroom, and the carer has private accommodation. Both benefit from independence — the parent is not under constant observation, and the carer has a private space to decompress from their caring role.
Two adult siblings. Where a family wants to house two adult children together, a 2-bed grannyflat Dublin allows them to share costs while each having a private bedroom.
Higher rental income priority. A 2-bed grannyflat Dublin rents for €1,300–€1,600/month in most Dublin areas — up to €4,800 per year more than a comparable 1-bed. If rental income is the primary purpose of the flat, the additional €22,000 build cost pays back in the higher rent differential in approximately 5–6 years.
Larger Dublin garden. If your garden can comfortably accommodate 40m² with good remaining open space, there is no reason not to build the larger flat — the additional space is permanently valuable.
The Rent-a-Room Threshold — A Critical Factor in the Size Decision
If you are building your grannyflat Dublin primarily for rental income under the Rent-a-Room scheme, the €14,000 annual threshold is an important factor in the size decision.
- A 1-bed grannyflat Dublin at €1,100/month generates €13,200/year — comfortably within the tax-free limit
- A 2-bed grannyflat Dublin at €1,400/month generates €16,800/year — €2,800 above the limit, making the entire amount taxable
If you build a 2-bed but rent it at €1,150/month (€13,800/year), you keep all income tax-free — but you pay more to build a larger flat than you need to for the income you are generating. The 1-bed is often the better financial decision if maximising tax-free rental income is the goal.
Discuss this with a tax adviser before deciding. See full pricing for all grannyflats Dublin sizes.
Frequently Asked Questions — 1-Bed vs 2-Bed Grannyflats Dublin
What is the price difference between a 1-bed and 2-bed grannyflat Dublin?
At GrannyFlats.ie, a 1-bed grannyflat Dublin (33m²) starts from €93,900 + VAT (~€106,577 incl. VAT) and a 2-bed grannyflat Dublin (40m²) starts from €115,900 + VAT (~€131,547 incl. VAT). The difference is approximately €22,000 + VAT (~€24,970 incl. VAT).
Do both 1-bed and 2-bed grannyflats Dublin qualify for the 2026 planning exemption?
Yes. Both our 1-bed (33m²) and 2-bed (40m²) grannyflats Dublin designs fall within the 32–45m² qualifying range for the 2026 planning exemption. Our studio (25m²) falls below the 32m² minimum and still requires planning permission.
Which size grannyflat Dublin is best for an elderly parent?
For a single elderly parent, a 1-bed grannyflat Dublin (33m²) is usually the right choice — it provides all the space needed for comfortable independent living while being less expensive to build and cheaper to heat. A 2-bed is recommended where the parent will live with a partner or requires a live-in carer.
What rental income does a 2-bed grannyflat Dublin generate?
A 2-bed grannyflat Dublin typically rents for €1,300–€1,600/month in most Dublin areas in 2026 — approximately €4,800 per year more than a comparable 1-bed. Note that at these rental levels, income is likely to exceed the €14,000 Rent-a-Room tax-free threshold.
Can I build a 2-bed grannyflat Dublin without planning permission?
Yes. Our 2-bed grannyflat Dublin design at 40m² qualifies for the 2026 planning exemption (32–45m², detached, single-storey, connected to existing services). Local authority registration is still required after construction.
Which size grannyflat Dublin is most popular?
The 1-bed grannyflat Dublin (33m²) is our most frequently built design. It provides the best balance of cost, liveability, and Rent-a-Room income optimisation for most Dublin families.
Book a Free Grannyflats Dublin Consultation — We Will Help You Choose
At GrannyFlats.ie, we help Dublin families make the 1-bed vs 2-bed decision at every free site assessment. We look at your garden, talk through who will use the flat, and tell you honestly which size makes most sense for your situation. There is no pressure and no obligation.
Book your free grannyflats Dublin consultation | See completed builds
Call: 01 615 5653 | WhatsApp: 087 288 9127
ll, Main Street Leixlip, Kildare. W23X725.
