A Janssens greenhouse comes in two very different looks: the classic Royal Victorian with its peaked roof and decorative ridge, and the clean-lined Modern with a single sloping roof. Both use the same Janssens aluminum frame and 4mm tempered glass. The real choice comes down to your home's style, how you will use the space, and your budget.
We sell both side by side in our Janssens greenhouse collection, and choosing between them is a common question. Below we compare them size by size, with real specs from the product pages and a simple way to work out value.
✅ Quick answer
- Same footprints: both styles come in 80, 150 and 200 sq ft (8x10, 10x15 and 10x20).
- Royal Victorian: classic gable roof, green or black, glass or hybrid roof, and the lower price per square foot.
- Modern: single sloping roof up to 9'7" tall, black frame, double hinged doors and extra push-out windows included.
- Pick Royal Victorian for traditional homes and serious growing on a budget.
- Pick Modern for contemporary homes, patios and a greenhouse you will also sit in.
What is the difference between a Janssens greenhouse in the Royal Victorian and Modern styles?
The main difference is the roof shape. The Royal Victorian has a two-sided gable roof that rises to a center ridge. The Modern has one flat slope, low on one side and tall on the other.
That one change affects almost everything else: how the greenhouse looks next to your house, where the headroom is, and how the inside feels. Underneath, both are built by Janssens, the Belgian maker, and sold in the US through Exaco.
What the two styles share
- Glass: 4mm tempered safety glass in single large panes, not small overlapping pieces.
- Seals: glass held in rubber seals instead of only metal clips, which helps keep heat in.
- Wall height: a 6'7" sidewall, about a foot taller than many kit greenhouses.
- Drainage: gutters with downspouts are included.
- Testing: TÜV and GS tested, a European safety approval.
Where they differ
- Roof: gable (Royal Victorian) vs single slope (Modern).
- Colors: green or black (Royal Victorian) vs black (Modern; ask us about other colors).
- Roof options: the VI34 and VI36 also come as a hybrid with a polycarbonate roof. The Modern is all glass.
- Doors and vents: different standard doors and window counts (see the table below).
Is a modern greenhouse right for a contemporary home?
If your house has flat rooflines, black window frames or a minimalist patio, a modern greenhouse usually looks more at home than a Victorian one. The Janssens Modern greenhouse has a slim black frame and one clean roof plane, so it reads more like a garden room than a traditional glasshouse.
The sloping roof also gives you a tall side of 9'7" on the M34 and M36 (8'10" on the M23). That tall wall is great for climbing tomatoes, citrus trees in pots, or a small seating area.
What comes with the Janssens Modern greenhouse
According to our product pages, the Modern models include:
- One set of double hinged doors with closers
- 2 roof windows (one with an automatic opener, one manual)
- Louvre windows with automatic openers (1 on the M23, 2 on the M34 and M36)
- 2 push-out side windows
- Gutters with downspouts
📌 Important: If you plan to set a Modern on a stem wall (knee wall), you will need a drop door kit and an extra glass panel above the door. Tell us about your base before you order and we will make sure the right parts ship with it.
Why do buyers still choose the Janssens Royal Victorian greenhouse?
The Janssens Royal Victorian greenhouse is the classic English design that has made Janssens a leading Victorian greenhouse supplier in Europe since 1999. It suits brick homes, farmhouses, cottage gardens and any yard where you want the greenhouse to be a focal point.
It is also the more practical choice for serious growers on a budget. Each size costs less than the matching Modern, and it includes extras the Modern pages do not list.
What comes with the Royal Victorian
- Foundation frame: a base frame is included, which many brands charge extra for.
- Misting system: included (you supply a hose to the faucet).
- Roof windows: 2 on the VI23, 3 on the VI34 and 4 on the VI36, with a mix of spindle and automatic openers.
- Louvered window: 1 on each model.
- Doors: a sliding door on the VI23 and double sliding doors on the VI34 and VI36. Hinged doors for the Royal Victorian are an upgrade.
💡 Tip: The spindle roof openers on the Royal Victorian let you lock a vent at a set opening. That gives you more control on windy days, when an automatic opener alone may open wide on a warm, gusty afternoon.
Janssens Royal Victorian vs Modern: how do the sizes compare?
Here is every current Janssens Royal Victorian and Janssens Modern greenhouse size side by side. Each style comes in the same three footprints, so you can compare like for like.
| Model | Size / area | Tallest point | Vents included | Price* |
|---|---|---|---|---|
 Royal Victorian VI23 |
7'9" x 10'2" / 80 sq ft | 8'6" | 2 roof + 1 louver | ~$9,800 |
 Modern M23 |
7'9" x 10'2" / 80 sq ft | 8'10" | 2 roof + 1 louver + 2 push-out | ~$15,400 |
 Royal Victorian VI34 |
10'2" x 15' / 150 sq ft | 9' | 3 roof + 1 louver | ~$11,400 |
 Modern M34 |
10'2" x 15' / 150 sq ft | 9'7" | 2 roof + 2 louver + 2 push-out | ~$19,700 |
 Royal Victorian VI36 |
10'2" x 19'11" / 200 sq ft | 9' | 4 roof + 1 louver | ~$13,900 |
 Modern M36 |
10'2" x 19'11" / 200 sq ft | 9'7" | 2 roof + 2 louver + 2 push-out | ~$23,300 |
*Prices checked in November 2026 for the all-glass version. Prices can change and sales may apply, so click the model name to see today's price.
Need something bigger? The 13x20 VI46 is covered in our Royal Victorian VI46 review. For a lower-cost Victorian look, see our Royal Victorian vs Junior Victorian size comparison.
📌 About prices: manufacturers update their prices during the year, and we often run sales and promotions. The price on the product page is always the current one. Prices in this article are a guide from when we wrote it (November 2026), not a quote or guarantee. Found a lower price for the same model at an authorized retailer? We offer a Price Match Guarantee - please check the rules first. Call us and we will confirm today's price and any current deals.
Which Janssens greenhouse gives the best value per square foot?
A quick way to compare greenhouse kits is the price for each square foot of growing floor. It does not capture style, but it shows what you pay for the look.
📐 Cost per square foot
Cost per sq ft = Kit price ÷ Floor area (sq ft)
Use the price on the product page today and the floor area from the specs.
🧮 Worked example: The Royal Victorian VI34 was about $11,400 when we wrote this (November 2026). $11,400 ÷ 150 sq ft = about $76 per sq ft. The Modern M34 was about $19,700. $19,700 ÷ 150 sq ft = about $131 per sq ft. Same floor space, so the gap is the price of the Modern design and its extra doors and windows.
Running the same math on all six models (November 2026 prices, estimates only):
- 8x10: VI23 about $122/sq ft, M23 about $193/sq ft.
- 10x15: VI34 about $76/sq ft, M34 about $131/sq ft.
- 10x20: VI36 about $70/sq ft, M36 about $117/sq ft.
Two things stand out. Bigger is cheaper per square foot in both styles. And the 10x15 and 10x20 Royal Victorians are the best value in the whole Janssens line for pure growing space.
Does the roof shape change headroom, heating and ventilation?
Headroom
In the Royal Victorian the tallest space runs down the middle, under the ridge. That suits a center path with benches on both sides. In the Modern the tall space is along one wall, so it suits tall plants or a table on the high side and low shelves on the short side.
Air volume to heat
If you plan to heat in winter, the air volume matters. You can estimate it from the specs.
📐 Greenhouse air volume (estimate)
Volume = Width × Length × Average height
Average height = halfway between the 6'7" wall and the tallest point, for both roof shapes.
🧮 Worked example: Modern M34: 10.17 ft × 15 ft × 8.08 ft (halfway between 6'7" and 9'7") = about 1,230 cubic feet. Royal Victorian VI34: 10.17 × 15 × 7.79 ft (halfway between 6'7" and 9') = about 1,190 cubic feet. The Modern holds only about 4% more air, so heating costs should be close.
For real heater sizes and monthly costs, see our guide to the cost to heat a greenhouse in winter.
Ventilation
The Modern M34 and M36 come with 6 vents (2 roof, 2 louver, 2 push-out). The VI34 has 4 and the VI36 has 5, mostly in the roof, where hot air collects. Both can take extra windows later, such as an additional roof window for the Royal Victorian. In hot climates, plan on shade and good airflow either way; our guide to cooling a greenhouse without electricity covers simple options.
Which style fits your home and garden?
Here is the simple guide we use when a customer calls us torn between the two.
Choose the Royal Victorian if...
- Your home is traditional: brick, stone, farmhouse, colonial or cottage style.
- Growing space per dollar is your top priority.
- You want a green frame, or a polycarbonate roof option for softer light.
- You like the included misting system and base frame.
Choose the Modern if...
- Your home has a contemporary look, black windows or a modern patio.
- You want a tall wall for climbing plants or potted trees.
- You prefer hinged doors and more side windows straight out of the box.
- The greenhouse will double as a place to sit, read or entertain.
🌿 Our verdict: For most growers, the Royal Victorian VI34 or VI36 is the smartest buy in the Janssens range. If the greenhouse sits near the house and has to match a modern design, the Modern is worth the extra cost. It is the better-looking choice on a contemporary patio.
What foundation and setup does an Exaco Janssens greenhouse need?
Every model needs a flat, level, square base. For the Modern, the product pages say a full concrete slab is not required. A perimeter foundation is enough, and anchoring the four corners in concrete is recommended.
The Royal Victorian ships with its own base frame, which you set on a level perimeter footing, pavers or a slab. Popular choices are pavers, a concrete curb, or a low stem wall for extra height. Our practical guide to a greenhouse foundation walks through each type and its cost.
Assembly: DIY or a crew?
Both styles are DIY kits, and the product pages recommend scaffolding for the roof work. If you would rather not build it yourself, we can help. We are a small, woman-owned business, and we can arrange an assembly crew in many areas, plus free shipping to the continental US.
⚠️ Safety first: Tempered glass is strong, but a full pane is heavy and awkward. Always have two people on glass installation, wear gloves, and never work on the roof in wind.
Can a Janssens greenhouse handle winter?
Both styles use the same 4mm tempered glass and rubber-sealed panes, so they behave much the same in cold weather. With a small heater, you can keep growing through the winter. Adding insulation on the north side helps hold the heat.
If you live with heavy snow, keep the roof clear after big storms. For the toughest climates, compare options in our guide to the most durable greenhouses for wind, snow and harsh winters. For a wider brand overview, see our Exaco Janssens hobby greenhouse buying guide.
Frequently asked questions
Is a Janssens greenhouse worth the money?
For most buyers, yes. You get 4mm tempered glass in single panes, rubber seals and a 6'7" sidewall, which many cheaper kits lack. The Royal Victorian VI34 and VI36 give the most growing space for the price.
Where are Janssens greenhouses made?
Janssens is a Belgian greenhouse maker, and our Royal Victorian product pages list them as made in Belgium. Exaco is the US distributor, and we are an authorized dealer.
Is the Janssens Modern greenhouse taller than the Royal Victorian?
At its tall side, yes. The Modern M34 and M36 reach 9'7", while the VI34 and VI36 peak at 9'. Both have the same 6'7" sidewall, so the extra height is only along the Modern's tall wall.
Can I get a modern glass greenhouse in green?
The Modern is listed in black. Call us if you would like another color and we will check with the manufacturer. The Royal Victorian comes in green or black as standard.
Which Janssens Royal Victorian greenhouse size should I buy?
We usually suggest the VI34 (10x15) or larger, because growers often wish they had more room. The VI23 suits small yards and patios. The VI36 has the best price per square foot.
Whichever Janssens greenhouse you choose, Royal Victorian or Modern, you are getting the same quality glass and frame. Browse the full Janssens greenhouse range, or call us and we will help you pick the right style and size.
Not sure which style fits your yard?
Talk to us directly. We will compare sizes for your space and confirm today's price and any current sale.
Call 678-408-8222 · [email protected]
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