Model Y leveling vs foam-and-air value
Havnby lists the FlatCore at $549 with a shaped 7.5-inch profile for the Model Y. Lost Horizon sells a thinner 4.5-inch foam-and-air mattress with an R-13 seller claim. On 1 October 2026, the Lost Horizon store listed its Model Y options at $199.99 and $229.99 and marked both unavailable.
Havnby FlatCore
Air-foam hybrid
Lost Horizon Standard
Foam + air
This comparison uses seller specifications and attributed public sources. We have not completed a matched hands-on test of both products. Our rating is the editors’ judgement, not a sleep test.How we rate
Quick verdict
Choose the Havnby FlatCore when the folded-seat slope is your main problem, when you drive a 2025–2026 Model Y, or when you want a 60-day trial. Choose Lost Horizon when a lower cabin profile and a published R-13 figure matter more, and when a Model Y variant is in stock on the day you order.
Choose Havnby FlatCore when
You drive a 2025–2026 Model Y. Havnby sells a FlatCore variant for it, and the Lost Horizon variants we checked name only the 2020–2024 Model Y.
All 4 reasonsWe read the Havnby product page and policy pages on 1 October 2026 with the US store setting. Lost Horizon’s size, depth, weight, R-13 claim and materials were recorded from the seller on 19 August 2026. We checked the Lost Horizon Model Y stock in its own store on 1 October 2026.
| Factor | Havnby FlatCore | Lost Horizon Model Y |
|---|---|---|
| Price checked 1 October 2026 | $549 for both Model Y year ranges | $229.99 with pump, $199.99 without; both unavailable in the Lost Horizon store |
| Vehicle fit | Model Y 2020–2024 and Model Y 2025–2026 variants | Model Y 2020–2024 on the Amazon variants we checked on 18 September 2026 |
| Size | 193 × 132 cm (76 × 52 in) | |
| Depth | 19 cm (7.5 in) at the seatback end, 7.9 cm (3.1 in) at the trunk end | 11.4 cm (4.5 in) |
| Weight | 5.1 kg (11.2 lb) | 6.1 kg (13.5 lb) |
| R-value | Not published | R-13 seller claim |
| Pump | Built-in 12V ABS pump | Rechargeable pump in the pump bundle only |
| Warranty | 3 years for orders from 1 June 2026 | 1 year |
| Next stepAffiliate links: we may earn a commission at no extra cost to you. | Shop · −10%: Havnby FlatCore Foam Mattress, code AWDReview: Havnby FlatCore Foam Mattress | Check price on Amazon: Lost Horizon StandardReview: Lost Horizon Standard |
$319.01The FlatCore cost $549 and the Lost Horizon Model Y pump bundle was listed at $229.99 on 1 October 2026. The Lost Horizon bundle was unavailable that day, so the gap applies only when the bundle returns at that price.
For the extra money, Havnby lists a shaped profile, an integrated 12V pump, a fitted sheet, a storage bag, a 60-day trial and a three-year warranty. Those are listed features. They do not prove that the FlatCore gives better sleep to every person.
Lost Horizon is the lower-cost choice when it is in stock. Amazon also sells a Lost Horizon Standard pump bundle. We did not record its Amazon price on 1 October 2026, so check the live listing before you compare totals.
Havnby FlatCore
7.5 in to 3.1 in, shaped
Havnby makes the FlatCore thicker at the seatback end and thinner at the trunk end, so that it fills the step of the folded Model Y seats. Havnby publishes no measured angle, and we did not measure one.
Lost Horizon Standard
4.5 in, one even layer
Lost Horizon uses foam and adjustable air in one 4.5-inch layer. It publishes no slope-correction shape. The lower profile leaves more room between the sleeper and the roof.
Havnby FlatCore
R-value not published
Havnby publishes no R-value for the FlatCore.
Lost Horizon Standard
R-13 seller claim
Lost Horizon publishes R-13 for its Standard model. We found no linked independent test, so we treat R-13 as a seller claim.
Havnby FlatCore
Built-in 12V pump, about 80 s
Havnby states about 80 seconds to inflate and about 90 seconds to deflate. The packed FlatCore measures 67 × 43 cm.
Lost Horizon Standard
Pump only in the bundle
Lost Horizon sells the Model Y mattress with and without a rechargeable pump. Pick the bundle you need before you compare prices.
The operator owns a FlatCore Model Y and a FlatCore Solo. His Havnby Solo vs Full Size video (the operator’s YouTube channel, 15 July 2026) shows both mattresses in a Model Y. It gives no measurement. Our owner experience covers the Havnby side only.
Havnby FlatCore
60-day trial, 3-year warranty
Havnby gives a 60-day sleep trial from delivery. An opened return can cost a condition fee: $15 or $30 on the returns page, $10 or $20 on the refund policy. Both pages were read on 1 October 2026.
Lost Horizon Standard
1-year warranty
Lost Horizon publishes a one-year warranty. Read the return terms of the store you order from before you open the mattress.
Affiliate links. We may earn a commission at no extra cost to you. Check the final total before you pay.Affiliate disclosure
AWDCart-tested 16 Sep 2026 The code page shows the full cart test.
We have no partner code for Lost Horizon. The link opens the seller page.
For Havnby, confirm the Model Y year range and the delivered total. For Lost Horizon, confirm that a Model Y variant is in stock and whether the pump is in the box. Read the Lost Horizon variant notes Compare the full Model Y mattress shortlist
For slope support, trial and warranty, the Havnby FlatCore lists more: a shaped 7.5-to-3.1-inch profile, a 60-day trial and a three-year warranty. Lost Horizon is thinner, publishes R-13 and costs less when its Model Y options are in stock.
The Lost Horizon Amazon variants we checked on 18 September 2026 name the Model Y 2020–2024 only. Havnby sells a separate FlatCore variant for the 2025–2026 Model Y.
Lost Horizon publishes R-13 for its Standard model. Havnby publishes no R-value. We found no independent test for either mattress, so we cannot name a measured winner.
Lost Horizon, at 4.5 inches. The FlatCore is 7.5 inches at the seatback end and 3.1 inches at the trunk end.
Not for the Model Y in its own store. Lost Horizon listed the Model Y mattress at $199.99 and the pump bundle at $229.99, and marked both unavailable. The Model 3 mattress-only option was available at $199.99.
We did not measure fit, slope, warmth or durability for either mattress.
Keep researching
By Tesla Mattress Guide Page last revised
