As the demand for low-carbon, energy-efficient heating systems grows across Edinburgh and the Lothians, more homeowners are considering air source heat pumps (ASHPs) as an alternative to traditional gas or oil boilers. But one of the first questions we hear at Latent Heat Edinburgh is:
“What type of air source heat pump is right for my home?”
In this guide, we break down the two main types of ASHPs — air-to-air and air-to-water — explaining how they work, how they differ, and which one might be the better fit for your property.
What Is an Air Source Heat Pump?
An air source heat pump is a renewable heating system that extracts heat from the outside air and uses it to warm your home. Unlike gas or oil boilers, it doesn’t burn fuel to create heat — instead, it transfers it using a refrigeration cycle.
There are two main types of air source heat pumps available in the UK:
- Air-to-Water Heat Pumps
- Air-to-Air Heat Pumps
Each system works slightly differently and is designed for different home layouts, usage patterns, and heating goals.
1. Air-to-Water Heat Pumps
🔧 How They Work:
Air-to-water heat pumps absorb heat from the air and transfer it into a wet central heating system. This means they heat water for use in:
- Radiators
- Underfloor heating
- Hot water cylinders
✅ Best For:
- Traditional homes with radiators or underfloor heating
- Properties looking to replace gas or oil boilers
- Households that need both space heating and hot water
⚙️ System Features:
- Requires an outdoor unit and indoor components (e.g., hot water cylinder)
- Can work with existing radiators (in many cases)
- Compatible with solar thermal and PV systems
💡 Efficiency:
Air-to-water systems typically operate with a COP (coefficient of performance) between 3.0 and 4.0, depending on home insulation and system design.
💷 Costs & Grants:
Air-to-water systems qualify for Home Energy Scotland Grants and Loans — offering up to £7,500 (more in rural areas) to support the cost of installation.
🔧 Offered By Latent Heat Edinburgh:
This is our most popular and recommended system for homes across Edinburgh.
2. Air-to-Air Heat Pumps
🔧 How They Work:
Air-to-air heat pumps extract heat from outdoor air and deliver it directly into the home using fan coil units (like air conditioners in reverse). These systems do not provide hot water.
✅ Best For:
- Open-plan homes, flats, or commercial premises
- Properties without wet central heating systems
- Buildings focused purely on space heating and cooling
⚙️ System Features:
- Uses internal wall- or ceiling-mounted blowers
- Often includes cooling function (like air conditioning)
- Easier and faster installation compared to air-to-water systems
💡 Efficiency:
Highly efficient for direct heating and cooling of rooms, particularly in well-insulated modern homes or commercial spaces.
💷 Costs & Grants:
Generally cheaper upfront than air-to-water systems, but not eligible for most government funding in Scotland (including Home Energy Scotland support).
🔧 Offered By Latent Heat Edinburgh:
We do not offer air-to-air systems but typically recommend air-to-water for full-home heating and hot water.
Air-to-Air vs. Air-to-Water: Quick Comparison
| Feature | Air-to-Water | Air-to-Air |
| Provides Hot Water | ✅ Yes | ❌ No |
| Compatible with Radiators | ✅ Yes | ❌ No |
| Works with Underfloor Heating | ✅ Yes | ❌ No |
| Cooling Capability | ❌ Not typically | ✅ Yes (optional) |
| Ideal for… | Whole-home heating & water | Space heating or open plans |
| Eligible for Grants | ✅ Yes (Scotland) | ❌ No |
| Installation Complexity | Moderate | Simpler |
Which System Is Right for You?
At Latent Heat Edinburgh, we tailor every recommendation to your home and lifestyle. Here’s a simple breakdown to help guide your choice:
- Choose Air-to-Water if:
You need hot water and central heating for a family home and want to replace a gas or oil boiler. - Choose Air-to-Air if:
You’re looking to heat (and possibly cool) a single zone, flat, or commercial unit — and don’t require hot water.
Our expert team offers free home surveys across Edinburgh to assess which system is best suited to your needs and budget.
Why Choose Latent Heat Edinburgh?
✅ MCS-Certified Installers
✅ Local Experts in Renewable Heating
✅ Grant Support & Application Help
✅ Full Design, Installation & Aftercare
Whether you’re upgrading your heating system, retrofitting an older property, or planning a new build, we can guide you through the best options available.
Book Your Free Consultation Today
Want to explore which air source heat pump is right for your home?
📞 Call: 0131 445 1457
📩 [email protected]
🌐 www.latentheat.co.uk
We’re proud to support homeowners across Edinburgh and the Lothians in the transition to cleaner, greener heating.