A Guide to Sustainable Retrofitting of Commercial Buildings

With investors tracking carbon data and local authorities tightening standards, the smartest route to better performance for your commercial building is usually retrofit, rather than rebuild.

Here is a practical guide to sustainable retrofitting of commercial buildings, including how solar PV can transform your HVAC upgrades and your overall Net Zero strategy.

Why Should I Consider Retrofitting?

It goes without saying that energy consumption and carbon disclosure has moved from “nice to have” to “must have”. Even if you’re not directly regulated, your largest customers probably are, so they’ll ask for your data.

Following on from this, it’s proven that energy efficiency cuts consumption and on-site generation reduces exposure to utility price spikes, giving you more control over your costs. Plus, efficient and low-carbon assets hold value a lot better.

For context, buildings account for a sizeable chunk of the UK’s emissions, with about 17% of national greenhouse gases used for space heat when you count direct emissions like gas.

The Main Types of Retrofitting

There are 4 different types of retrofitting that can all be used together:

1. Materials

Examples: Insulation upgrades, improved glazing, airtightness, draught-proofing.

Why? Reduces base heating/cooling loads so your HVAC, and renewables go further.

Considerations: Plan for moisture management and ventilation to maintain indoor air quality.

2. HVAC Upgrades

Examples: High-efficiency heat pumps (air or water source), variable speed drives, heat recovery, demand-controlled ventilation (CO₂/VOC sensors), optimised controls and zoning, hydraulic balancing.

Why? HVAC is often the largest energy consumer in commercial buildings, so efficiency changes here make the biggest impact.

Considerations: Good Building Management Systems (BMS) are required to ensure efficient set-points to increase savings.

3. Lighting & Controls

Examples: LED upgrades, high-efficiency drivers, daylight/occupancy sensors.

Why? Lighting typically consumes around 20% of electricity in commercial and industrial buildings, and LEDs plus controls can halve that in many estates.

Considerations: Design your lighting levels for the task as overdoing the lights wastes energy as well as harms staff comfort.

4. Power, Monitoring & Digital

Examples: BMS/analytics, automated fault detection, power factor correction.

Why? You can’t improve what you don’t measure, so collecting data identifies waste and validates your business case.

Why Solar PV Pairs Well With HVAC

Did you know? When you integrate solar PV with your HVAC system, you unlock many benefits including:

• Load Matching: Cooling demand typically rises when the sun is out. Daytime PV output can directly feed chillers, heat pumps, and ventilation fans, reducing peak imports and demand charges.

• Cheaper Heat: Using high-COP heat pumps is most efficient when the electricity is self-generated. You cut Scope 2 emissions and shrink exposure to the grid at the same time.

• Battery or Thermal Storage: By pairing solar with hot-water cylinders, buffer tanks, or batteries to store electricity generation, you can run HVAC at optimal times (pre-cooling or pre-heating).

• Grid-Friendly: Better alignment between on-site generation and HVAC reduces grid strain and can improve your operational ratings.

How to Retrofit Your Business’ Building

• Bundle Retrofitting Measures: Pair short-term retrofits (lighting, controls) with long-term ones (heat pumps) to increase your ROI.

• Model Self-Consumption: Solar PV value is driven by how much you use on-site. By aligning this with HVAC operating hours, you reduce import costs and stabilise utility bills.

• Report Accurately: Map every kWh saved or generated to Scope 2 (and upstream Scope 3 where relevant) using consistent methods across sites.

Why Partner With Noble Green Energy?

From logistics distribution centres to offices and manufacturing, our team understands how different building types and industries function. Noble Green Energy manages the whole solar PV journey, starting with feasibility and yield modelling through to installation and O&M. We can seamlessly integrate your system with your HVAC and controls strategy without disrupting operations.

At Noble Green Energy, we work with Building Contractors and Mechanical & Engineering (M&E) contractors across the UK to deliver tailored solar PV installations for commercial and industrial buildings. Find out more: https://noblegreenenergy.co.uk/industries/mechanical-electrical-building-contractors/

Contact us to arrange a consultation and develop a tailored retrofit and solar PV roadmap for your commercial building.