Commercial Mortgage vs Residential Buy-to-Let: What's the Difference?

🚀 How Each Product Is Assessed

The biggest difference between the two products isn't the rate or the LTV — it's what the lender actually underwrites.

• Residential BTL — the lender focuses on the landlord's personal income, credit history, and experience. The property is treated primarily as security.
• Commercial mortgage — the lender focuses on the property's income-generating capacity, the tenant's covenant strength, and the loan-to-value. The landlord's personal finances matter less.

In practice, this means a residential BTL lender will decline a strong commercial property deal because the landlord's tax returns don't show enough earned income. Equally, a commercial lender will look straight past the landlord's salary and ask how much rent the tenant is paying and how secure that tenant is.

Tenant Type: AST vs Commercial Lease

The tenancy type drives which product you need. Residential BTL mortgages are designed for properties let to individuals under an Assured Shorthold Tenancy (AST). Commercial mortgages are for properties let to businesses under commercial leases — offices, shops, warehouses, industrial units, restaurants, hotels, or mixed-use premises.

Commercial leases are typically longer than ASTs (often 3, 5 or 10 years), more varied in structure, and sometimes include rent reviews, break clauses, or tenant-only obligations. This complexity is one reason commercial mortgage underwriting takes longer and why commercial rates are usually slightly higher.

If the property has any element of commercial use — even a flat above a shop — most residential BTL lenders will refuse it. Specialist commercial lenders will usually accept it.

✅ Rate Comparison: Where Each Product Sits

In the current UK market, typical rates look roughly like this:

• Residential BTL fixed rates — starting around 4.5%–5.5% for a standard 5-year fix, depending on LTV and lender
• Residential BTL variable rates — slightly lower starting point but exposed to base rate movements
• Commercial mortgage rates — starting around 5.5%–7% for prime property with strong tenants, higher for more specialist assets

Commercial rates are usually 1%–2% higher than residential BTL at any given point in the cycle, reflecting the longer valuation process, the more complex underwriting, and the wider range of property types involved. But commercial rental yields are typically higher too, often 6%–10% gross compared to 4%–6% for residential BTL in many UK regions.

LTV: How Much You Can Borrow on Each

LTV is where the two products look more similar than people expect. Both residential BTL and commercial mortgages typically max out around 75% LTV for standard deals — though some specialist lenders will stretch higher on particularly strong cases.

• Residential BTL — most lenders cap at 75% LTV, with some allowing 80%+ for strong borrowers on standard property types
• Commercial mortgage — typical maximum of 70%–75% LTV for owner-occupied or investment commercial property
• Refinance deals — both products can sometimes go to higher LTVs on a remortgage with strong existing security

The actual LTV you'll be offered depends far more on the strength of the property, the tenant, and your track record than on the product type itself. A commercial property with a 10-year lease to a covenant-strong tenant will usually secure a higher LTV than a residential BTL on a tired flat in a softer location.

📞 Lending Criteria: What Each Lender Actually Wants

Residential BTL lenders care about:

• The landlord's personal income (typically £25,000+)
• Personal credit history
• Existing property portfolio size
• Experience as a landlord
• Stress testing rental income at higher rates (typically 5.5% or more)

Commercial mortgage lenders care about:

What Commercial Mortgage Lenders Specifically Assess

• The property's rental income and lease length
• The tenant's covenant strength — how likely they are to keep paying
• The property type and location
• LTV and projected yield
• The landlord's experience with commercial property specifically

Neither product is easier to qualify for in absolute terms — they're just easier for different borrowers. A first-time landlord with a strong salary may find a residential BTL easier. An experienced investor with a strong-tenant commercial building may find the commercial mortgage easier.

🇬🇧 When to Choose Which

A simple way to think about it:

• Use a residential BTL mortgage when the property is let to individuals on ASTs and your personal income and credit are strong
• Use a commercial mortgage when the property is let to a business under a commercial lease, or when the property has any commercial element
• Use a commercial mortgage when you want the lender to focus on the asset's income, not your personal tax returns
• Use a commercial mortgage when you're buying mixed-use property, HMO-suitable property that exceeds HMO licensing thresholds, or semi-commercial premises

The wrong product usually means a declined application at best, and a forced refinance at higher cost at worst. Get the product fit right before you start talking rates.

🏁 Hybrid Scenarios Worth Knowing

Some properties sit between the two worlds. The common hybrid cases we see:

Mixed-use premises — a shop with a flat above. Most residential BTL lenders will refuse this; commercial lenders will usually accept it, often as a single combined facility.

HMO property — a house in multiple occupation. Depending on the size, licensing and council, this can fall under residential BTL with a specialist lender, or commercial lending if the tenant structure is corporate.

Commercial-to-residential conversion — buying a commercial property with planning for residential conversion. Most lenders will treat this as commercial at acquisition, then allow a refinance to a residential product once the conversion is complete and the property is let.

Owner-occupied business premises — if you're buying premises for your own business, that's commercial lending but typically with a different rate environment than investment commercial.

Each of these scenarios has lenders who specialise in them. A broker who places deals across both residential and commercial panels will know which is which.

❓ FAQs: Commercial Mortgage vs Residential BTL