New Build SAP
Energy Performance Certificates in Waltham Cross, Hertfordshire
We provide SAP calculations and Energy Performance Certificates (EPCs) for new build dwellings, conversions and extensions, with comprehensive support throughout each stage of regulatory compliance. New build services commence from 195.00, with a strong recommendation for design-stage SAP calculations to ensure conformity with Part L Building Regulations (2022). These services include Predictive Energy Assessment (PEA), U-Value analysis, and the preparation of as-built SAP calculations alongside EPCs required for completion and marketing purposes. Conversion services, starting from 175.00, address change of use developments and the subdivision of properties into flats, ensuring compliance with Part L (2022) and requiring full SAP EPCs produced by an OCDEA. Extension services, from 95.00, focus on compliance with glazing limitations of 25% of floor area, offering simplified assessment routes, while SAP calculations are required where extensive glazing or folding doors are proposed.
Highlights & Specialties
- Design-stage SAP calculations ensuring Part L 2022 compliance
- Predictive Energy Assessments and detailed U-value calculations provided
- As-built SAP calculations for building completion and EPC
- Expert support for new builds, conversions, and extensions
- OCDEA specialists ensuring full compliance and accurate certification
- Guidance through Building Control requirements and energy standards
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Contact Details
Products & Services
SAP Calculations
read moreWe ensure that SAP calculations are prepared in line with building control expectations enabling compliance with Part L for both new build and extension projects Working alongside architects or directly with clients we help establish practical and cost efficient approaches while producing both predictive and final EPC outputs derived from the assessments consistently throughout process
Energy Performance Certificates
read moreWe provide SAP calculations for EPCs covering new builds, conversions, and extensions. Our Domestic EPC assessors have over a decade of experience with existing dwellings in North London and Hertfordshire. We remain up to date with MEES requirements and assist landlords in understanding EPC ratings. We support property owners in working towards a C rating and identifying suitable options.
Overheating Assessment
read moreWe offer a streamlined assessment service for overheating calculations in line with Part O of the Building Regulations. Our approach considers window dimensions and ventilation openings to support compliance. Where extensive south-facing glazing or bi-fold doors are present, thermal dynamic modelling is typically required. We are able to recommend a suitable assessor.
Water Efficiency Calculations
read moreWe prepare detailed Water Efficiency Calculations under Part G for new dwellings, conversions and extensions. These assessments are necessary for Building Control approval before completion sign-off can be granted. They verify predicted household water use against national requirements and ensure compliance with statutory standards. Providing the calculation at both design and completion stages helps maintain compliance and keeps your project on track.
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Savidh Thebe
Feb 15, 2026
Dean was thorough with his work and the turn around period was within a day. He was very knowledgable and his advice on saving was helpful. I would definitely recommend him
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Roberto Essuman Rbbe
Jan 29, 2026
I have had the pleasure of working with New Build SAP on a number of projects over the past year. Their professionalism and clear, reliable communication have been outstanding, and I would not hesitate to recommend them.
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Julie Bayliss
Jan 27, 2026
Excellent service - prompt, efficient, and great value. Highly recommend. Thanks for all your help!
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Dan Brooks
Jan 26, 2026
Great, quick service. Very attentive and prompt replying to any questions. I would recommend their services.
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Key People
Dean Miller
Ownerread moreAt New Build SAP we believe in providing a personal service, caring for each clients individual needs and providing this service at a reasonable price. Our attention to detail ensures that every project is handled with the utmost care. We will help you navigate this tricky area of legislation.