Heat Pump System Upgrades
& Retrofits in Hampshire

Upgrade your existing heat pump system to deliver the performance it should have from the start — better emitters, smarter controls, and measurably lower running costs.

15+ years in HVAC. Specialist in retrofitting and upgrading underperforming heat pump installations.

Heat pump system upgrades and retrofits cover the improvement of existing heat pump installations that are not performing to their potential. This might involve upgrading radiators to work at lower flow temperatures, adding underfloor heating to key rooms, replacing an inadequate hot water cylinder, or reconfiguring the hydraulic layout for better efficiency.

Many heat pump systems installed during the early adoption period — or fitted quickly under government incentive deadlines — were installed with compromises. Standard radiators were left in place, weather compensation was not configured, and hot water cylinders designed for boilers were reused. These systems work, but they work inefficiently.

This service is for homeowners who want to improve their existing heat pump system without replacing the heat pump itself. In many cases, upgrading the components around the heat pump — the emitters, controls, and hot water system — delivers a bigger improvement than replacing the unit.

Craig Ball's extensive experience in commissioning and optimising underperforming systems means he can identify exactly which upgrades will deliver the most impact for your specific installation.

A heat pump running at 55°C flow temperature because the radiators are too small has a COP of around 2.0 — meaning you pay for 1kW of electricity to get just 2kW of heat. The same heat pump running at 35°C with correctly sized emitters achieves a COP of 3.5–4.0, nearly doubling your efficiency.

Many homeowners were told their existing radiators would be fine. Technically they might heat the house, but only by running the heat pump at high flow temperatures that eliminate the efficiency advantage over a gas boiler.

An old or undersized hot water cylinder with a small coil surface area forces the heat pump to run at higher temperatures for longer to heat your water. This is one of the most common but easily fixable causes of high running costs.

Without smart controls or proper zoning, your heat pump heats your entire house to the same temperature at all times — wasting energy on rooms that are unoccupied or need different temperatures.

Radiator upgrades are the most common retrofit we carry out. We calculate the required output for each room at the target flow temperature (typically 35–45°C) and specify replacement radiators that meet this requirement. Double-panel, double-convector (Type 22) or larger radiators are often needed, or in some cases, fan-assisted radiators that deliver high output from a compact size.

Underfloor heating retrofits are increasingly popular as a complementary emitter to existing radiators. Wet underfloor heating running at 30–35°C is ideally matched to heat pump flow temperatures and provides excellent comfort in living rooms, kitchens, and bathrooms.

Hot water cylinder upgrades involve replacing a standard boiler cylinder with one designed for heat pump use. Heat pump cylinders have larger coil surface areas (typically 3–4 m²) to transfer heat efficiently at lower flow temperatures. This reduces reheat times and minimises immersion heater usage.

Hydraulic modifications may include adding or resizing a buffer tank, installing a low-loss header, adding zone valves for better control, or reconfiguring pump arrangements. The goal is always to ensure the heat pump operates within its designed flow rate range across all operating conditions.

Control upgrades range from simple programmable thermostats to smart zoning systems that learn your schedule and adjust heating accordingly. Weather compensation sensors can be added or relocated for more accurate readings. Smart thermostats with heat pump-specific algorithms (such as Homely or Vaillant's myVAILLANT) can further improve efficiency.

For properties with older heat pumps approaching end of life, we advise on whether upgrading components around the existing unit is worthwhile, or whether a system-wide replacement with a newer, more efficient heat pump is the better investment.