SAP10.1 – the future for electric heating

One of the biggest challenges for the industry has always been SAP and EPC calculations.

These are directly related, as a SAP pass is needed to produce an EPC and both are required for a property to be sold or rented.


Here we talk about the latest SAP calculation (SAP10) and how it affects the HVAC industry.

What is SAP?

SAP stands for Standard Assessment Procedure. It’s the calculation methodology set out by the UK government to calculate the energy performance of buildings. It’s also a requirement of the Building Regulations for new builds. The methodology was developed by the Building Research Establishment (BRE) in 1992, as a tool to help deliver its energy-efficiency policies.

SAP calculations:

  • Assess how much energy a building will consume when delivering a defined level of comfort

  • Determine energy-related running costs

  • Is used for EPC (Energy Performance Certificates)
  • Shows compliance with Part L of the Building Regulations

The SAP calculation takes into account a variety of factors (heating, lighting, renewable technologies and building construction) to provide a number between 1 and 100. The lower the number, the more expensive a property will be to heat and the higher the CO2 emissions. If the number exceeds 100, it effectively “exports energy”. For example, excess energy produced by solar panels is fed back into the grid, as it’s produced but not used.

Why is the current SAP challenging for the industry?

The current methodology used for SAP2012 uses vastly outdated figures to determine the emission difference between gas and electricity. For example, electricity was 0.519 kgCO2/kWh and gas only 0.216 kgCO2/kWh, a whopping difference of 58%.

This means that for every electricity kWh, it releases 0.519kg of CO2. This also directly affects the EPC, as the higher the carbon factor the worse a property’s ERP rating. 

Gas always came out on top according to SAP calculations and electric scored poorly on EPCs. Combine this with cheaper running costs, gas was the favoured heating option for specifiers and homeowners, whilst other forms like high heat retention storage heaters were preferable in EPCs.

The accuracy at showing how energy is used in a property is also another criticism of SAP2012, as well as how well the design is being constructed. Future SAP calculations, like SAP10.1, will be more detailed in how they calculate building energy use and in the audit trail of how designs and constructions are assessed and verified. 

For example, the standardised heating patterns had differences between weekdays and weekends. Further studies have shown this is not necessarily the reality, therefore SAP10.1 has changed to apply the same daily heating pattern, regardless of the day of the week. This will reduce energy use and costs across the board.

Seems ludicrous that a carbon-heavy heating system like gas is not only cheaper to run, but is more favourable than one that uses renewable energy doesn’t it? This was the question many of us in the HVAC industry needed answering. For a long time, electric heating has been considered our best foot forward to tackling net-zero heating solutions in line with government climate targets, but SAP2012 told us this wasn’t the case. The answer starts with SAP10.1.

What do we know about the latest SAP10.1 changes?

SAP10.1 is the most recent update on how homes will need to be designed to pass Building Regulations in the very near future. Whilst it cannot be used in an official capacity, it was published to allow designers to plan their housing specifications more in line with the current market.

SAP10.2 is likely to be the official version published alongside the new Part L of the Building Regulations in late 2021.

If you’re a HVAC manufacturer or supplier, the latest SAP calculations, SAP10.1, are BIG news.

SAP10.1 reduces the electricity carbon emission factor to 0.136 kgCO2/kWh from 0.519 kgCO2/kWh. Making it the most environmentally friendly and best-performing heating method for EPC ratings and SAP. Combine this with the urgent need to decarbonise heat, it’s huge news for the future of HVAC.

The current SAP10.1 draft now heavily penalises gas, due to the reduction of electricity carbon emission factors. This means that electric heating is now the front runner, especially highly efficient heat pumps. One of the main reasons for this emission reduction is the increased use of green energy (hydro, solar but predominantly wind farms) and the impact on the energy grid.

As the grid continues to become much greener, electricity will be the cleanest source, working hand in hand with net-zero targets and the government’s plan to ban gas boilers in new builds by 2025.

SAP10.1 – the future of heating

The proposed SAP calculations will change the way heating systems are designed for residential developments in order to comply with Building Regulations. As designers can now use figures which are closer to reality, electric options are suddenly much more attractive over CHP and gas.

Developers and specifiers might lean more towards electric radiators and panel heaters, electric underfloor heating and/or heat pumps as a primary heat source. Heat pumps are becoming the go-to option for space and water heating as they provide the most energy-efficient solution on the market. 

Hot water heaters are also expanded with heat pumps, immersion heaters, electric water heaters and possibly hydrogen-based products as this technology develops further.

Electric heating already has many benefits, and these are only amplified with the SAP10.1 changes:

  • Low maintenance as no annual servicing costs.
  • Don’t burn fuel to generate heat so eliminates the risk of carbon monoxide emissions and explosions.
  • No water-filled pipes so less risk of damage to a property from leaking or burst pipes.
  • No heat loss between the power source and heat output.
  • Increased temperature control with added energy-saving functions like Open Windows, Presence Detect and Consumption meters.
  • Connectivity features like Bluetooth or WiFi for smarter and more efficient control via apps.
  • Easy and quick to install, e.g. they can be installed during the 2nd fix wiring stage.

Due to the proposed SAP10.1, there has already been an increase in off-site construction, most notably bathroom pods as they lend themselves to a Plug’n’Play style for electric underfloor solutions, where it’s easily installed off-site as part of the pod and simply plugged in when installed on-site.

In fact, the GLA has already stated that when estimating CO2 emission performance against London Plan policies, the SAP10 factors must be used until the government updates Part L of the Building Regulations. In addition, following the most recent Future Homes Standard consultation, the government has reinstated its commitment to heat pumps.

However, cost increases for homeowners are a concern as electricity is still more expensive than gas.

Whilst gas has a lower price per kWh, it’s based on a diminishing natural source that’s also not considered to be a “green” option as it's carbon-heavy with no alternative for renewable sources. Therefore, in our opinion, the price should rise in accordance with this change.

Government and energy companies need to be fairer and consider that if gas is to be phased out to meet climate change targets, the cost must reflect this switch to greener energy.

Energy bills shouldn’t be significantly increased, simply because they install a more energy-efficient and zero-carbon option

In our opinion, running costs are currently the biggest sticking point in making the switch from gas to electric.

Further consideration must be taken to help homeowners overcome this barrier to a better future. Levies, grants and incentives could help.

As we move towards decarbonising the electricity grid, electric heating should become the natural choice and the most attractive option. SAP10.1 is the first step in helping customers discover electric heating solutions for space and water that balance the comfort, control, cost and efficiency that our world now demands.

What happens next?

At the time of writing this article, SAP10.1 is the latest unofficial draft of SAP10 and there will most likely be a further official iteration (SAP10.2) prior to its potential launch in 2021.

Those who thought electric heating wasn’t going to be a viable or favourable option, may now just live to regret it.

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