Priddy's Hard

Updated: 14 October 2024

Location: Gosport

Developer: VerdeGO Group

Number of units: 21 Terraced and Semi-detached Houses


Aim(s) of Project:

Demonstrate benefits of MMC construction throughout the building process along with PV, Battery Storage, Infra Red ceiling mounted heating panels with fractional hot water cylinder using AI functionality produces low energy zero carbon homes that outperform SAP and EPC that are a cheaper to run and maintain and as an alternative to ASHP 


Construction method: Advanced Closed Panel CAT2 Timber Frame, Insulated offsite manufactured raft foundations with brick façade

Energy Compliance method: SAP 10

Overheating compliance method: -


Construction start:  January 2020

Construction finish: May 2021

North Whiteley picture of house

Overview of Project and Specification

The aim of the project is to demonstrate benefits of MMC construction throughout the building process along with:

  • 4.5kWp photovoltaic panels,
  • 6.5kW battery storage,
  • Infra Red ceiling mounted heating panels
  • Smart fractional hot water cylinder (fed from the PV)
  • AI functionality


The battery storage and AI give the ability to load shift to off peak times offering the opportunity for grid Demand-Side Response.


The hypothesis is that this will perform better than “predicted” in SAP and in practice could be cheaper to run and maintain than an air source heat pump.


The fabric uses Cat 2 closed panel timber frames were supplied by VerdeGO Timber Frames with a wall U-value of 0.17 and a designed airtightness of 5m3/hm2@50Pa.  Intermittent extract ventilation is used.


Key learnings


  • Infra-red is simple to install and removes work from the M&E package. All work carried out by electricians.
  • Customers are very accepting of AI. Most people are using the “Agile” Octopus tariff.
  • AI is commissioned by Wondrwall.
  • No moving parts and no maintenance required by occupants or trades.
  • Mixergy smart cylinder is easy to instal and use.
  • Have not had to change fabric performance to obtain better performance.
  • This specification avoids the need for MVHR. Having installed MVHR in the past VerdeGo find Intermittent Extract Ventilation easier to instal, easier to use and requires less maintenance.

Performance evaluation


  • The energy cost of the homes varied between £540 and £1452 for the first year. The average was £1307.
  • The space heating use was between 7% and 86% of that shown in SAP with the average being 40%
  • Occupancy and occupancy behaviour had a greater impact on hot water use, which varied between 20% of that shown in SAP and 205%, with the average being 108% (very close to SAP). The variation in behaviour can be clearly seen in the homes containing 2 occupants (11 homes in total) where the hot water use varied between 20% of that shown in SAP and 183%. With an average of 100%.
  • Solar generation covered 41% of the energy consumption; even in the worst month January, solar covered 9% of the energy consumption.
  • Of the energy that was imported from the grid, 58% was imported at cheaper, lower carbon off-peak times, reducing running costs.
  • Half of the solar generation was exported to offset the cost of importing energy, further reducing energy bills.
  • The Build Test Solutions SmartHTC test was used on two of the homes and the fabric was 9% and 20% better than had been predicted by SAP
  • Unregulated energy represented between 54% and 79% of the energy consumed by the homes showing the importance of designing homes to address cooking, washing, drying etc.


The numbers