About Us
We're Cosier
Where We Operate
We’re on a mission to make it easier for homeowners to switch from gas boilers to air source heat pumps.
Our experienced team will design a heat pump system tailored to your home and install it across
London, Hertfordshire, Bedfordshire, Cambridgeshire, Essex, Norfolk and Suffolk.
Getting the UK off fossil fuels like gas and oil is one of the biggest challenges of our time.
At Cosier, we’re using smarter tools and better design to give you a great service
and a heat pump system that will perform brilliantly and last for years.
We’re also accredited installers for Sunamp Thermino heat batteries, which provide instant hot water in half the space of a normal hot water cylinder.
Call our friendly team on 02080 50 40 30 for expert advice or
book an initial design consultation.
We operate in the area shown in orange below. If you’re slightly outside of this area, get in touch and we’ll see if can help.
Meet the Team
Dina - Head of Heating System Design
02080 50 71 57
Dina leads the design of every Cosier heating system. With a Master’s degree in Engineering for Energy Technology and years of experience working on high-end, energy-efficient systems in Germany, she’s an expert in how to make homes warm, comfortable, and efficient.
Dina takes the time to understand your home and how you use it — your comfort preferences, daily routines, and any concerns about switching from gas or oil boilers. She then personally ensures that your heat pump is tailor-made for your home, optimized using technical calculations (like heat loss calculations and hydraulic balancing) that are crucial but often overlooked.
Dina’s always on the lookout for innovative technology to improve home heating and energy efficiency.
Feel free to call Dina on 02080 50 71 57 to discuss your requirements.
Mark - Head of Operations
02080 50 90 41
Mark oversees every Cosier installation and will be your main point of contact once work begins. With over 24 years’ experience in plumbing, renewables, and air-source heat pumps, Mark is one of the UK’s most experienced professionals in the field.
He began installing heat pumps across East Anglia long before they were mainstream, helping rural homes move away from expensive oil boilers. Since then, he’s trained countless installers, managed multiple installation teams, and even set up the UK training centre for a global heat pump manufacturer.
As an accredited installer of Samsung and SunAmp systems and a qualified F-Gas technician, Mark’s seen and solved almost every heating challenge — from small cottages to large estates. With Mark leading your installation, you’re in very capable hands.
Ben Dyson - Founder & Managing Director
02080 50 90 51
Ben founded Cosier to help homeowners make the switch from gas boilers to air source heat pumps — easily, confidently, and affordably.
After a career in finance and technology, Ben retrained in home heating and renewable energy before assembling a team of expert designers and installers who share his obsession with quality and customer care.
As Managing Director, Ben is responsible for ensuring every customer ends up with an efficient heating system and a comfortable, low-carbon home. If you ever have a question or issue, you can reach him directly at 02080 50 90 41.
Our Memberships & Certifications
Microgeneration Certification Scheme
Membership Number: IAA10255
We are certified to install air source heat pumps under MCS. MCS is the UK’s quality mark for renewable energy systems like solar panels and heat pumps. They set the standards you should always expect from an MCS certified installer and the products they use, whether your installation is going into your home or business.
Installation Assurance Authority
Membership Number: IAA10255
Our certification body is The Installation Assurance Authority (IAA). They assess us annually to confirm we’re meeting the MCS standards.
HIES
Membership Number: CHL/A/1718
We are members of the HIES Consumer Code, which provides a number of protections for you, including deposit protection and a 2-year insurance backed guarantee.
BESCA
Membership number: HV111782
We are members of the BESCA Competent Persons Scheme for the installation of air source heat pumps.
Refcom (F-Gas)
Membership number: REF1023819
We are certified by Refcom for handling fluorinated gases (which are used in air-source heat pumps).