28. The Bottom Line

Nobody tells you how much their project really cost.

I wish they would. It would be so helpful to clients to understand what’s involved in a project and get a realistic idea of cost. So, I’m putting my cards on the table with a detailed breakdown of how much this project cost.

So, what was the bottom line?

The overall cost was £369,430.14 including VAT.

What does this include?

Everything! From the initial thermal imaging and air tightness survey back in October 2021 through to the hooks I’ve added to the bathroom doors after my first visitors stayed this summer of 2024.

Professional fees and surveys: These are the fees for the architect, supported by specialist consultants - e.g. for the Mechanical Ventilation with Heat Recovery (MVHR) and the Air Source Heat Pump (ASHP) heating and hot water system. Collectively these came to around £21,000. In addition, there are several surveys needed to inform the design. The most expensive of these (at £1,195) was a topographic survey on which the architectural drawings are based. Also included in this category are fees for the planning application and Building Regulations, which totalled just under £1000.

Main Contractor’s Labour: What is says on the tin – the cost of people to build the project. This includes not only the Main Contractor’s team, but also sub-consultants employed by the Main Contractor such as the electrician, plumber and joiner.

Main Contractor’s Materials: Again, a straightforward category – all the timber, tiles, bricks, blocks, render, nails, screws and other bits and bobs (lots and lots of airtight tape!) needed to build the building. Also included in this total are ‘prelims’ – skip hire, portaloo, and so on.

Specialist Contractors: These were contractors I employed directly as Client, as opposed to other specialists employed as sub-contractors to the Main Contractor. These include works undertaken before the main project started on site (like the removal of the asbestos ceiling in the garage) and discrete elements of the main project, such as the supply and installation of the ASHP.

Free issue items: These are items supplied by me, as client, to the builder at no cost to the builder (but obviously a cost to me!). This category includes everything from the big-ticket items (10 triple glazed windows and doors at £19,390, the kitchen and appliances, and the bathroom fittings) down to coat hooks at £12.35. I’ve also included a few items of new furniture here – e.g. Ikea Billy Bookcases for the living room, and a second-hand drawer unit from eBay for the bedroom. These wouldn't normally be included in a building budget, but I'm treating this differently as it's my personal budget - I want to know exactly how much I've spent.

Insurance, Rent and Removals: The build process involved stripping the building back to a shell so that we had a simple volume to make airtight. There was no question of continuing to live in my home during construction, so I had to put my stuff in storage and move out. I was lucky that costs of renting a room were minimal thanks to ‘mate’s rates’. I’ve written in Blog Post No.12 about ‘The Boring Stuff’ – I had no idea how expensive Renovation Insurance is!

Is there anything you’ve left out?

No, the costs include absolutely everything, right down to toilet roll holders and cushions for the dining area bench seat.

The project included some significant hard landscape remodelling of the back garden to integrate it with the new stepped access from the living room but no soft landscaping. So now it’s time to spend some money but – more importantly – time on my garden to get it looking as good as the house.

How much extra did it cost to build a Passivhaus?

It’s difficult to completely separate out those building elements that were required to create an energy efficient home from the general refurbishment. However, there are some things that are obvious and can be accounted for reasonably easily, such as:

• work to the floors to insulate them;

• internal wall insulation;

• the additional cost of triple glazing over replacement double glazing;

• the supply and fitting of the MVHR system;

• stripping out and rebuilding the internal stud partitions – we would have worked mostly with the existing layout if this approach hadn’t been a key part of making the building super airtight; and

• professional fees would have been reduced, as we wouldn't have needed the same level of expertise.

An overall rough guesstimate is around £86,000 extra to get pretty close to Passivhaus retrofit standards – an uplift of around 30% on the whole-house refurbishment.

How could you afford it?

I was in the fortunate position of owning my house in London outright. So when I decided to relocate to Kendal, I made a plan to buy a new house at a price that would leave a big enough budget for a major retrofit.

Will you make this money back?

There are two ways of recouping the cost of the project: through 'payback' on reduced energy bills and through the uplift in value when I sell the place.

I won't make all of the money back. But that's not why I did this project. My main aim was to create a really comfortable ‘forever’ home that I can enjoy living in. No draughts, no worries about energy bills, fantastic air quality and a living space that works for my lifestyle.

I had some secondary aims:

• refurbishing the whole house now (it has a new roof, for example) means I shouldn’t have to worry about big maintenance bills in the future;

• as an architect (but not the right sort for this project!), I’ve long been curious about Passivhaus design and wanted to know more. I’ve really developed my knowledge and understanding, and am continuing to learn; and

• wanting to do the right thing by minimising my environmental impact and sharing the learning and experience as widely as I can.

Was it worth it?

Yes!

#EcoBungalow #Passivhaus #Passivehouse #EnerPHit #Retrofit #DeepRetrofit