Hardwood Logs or Softwood Logs

For the purposes of firewood, hardwoods are most commonly oak, ash, elm, beech, birch, sycamore, aspen, cherry and alder. Of course there are many more hardwood species.

These are broadleaved deciduous trees and they tend to be slower growing and the wood is more dense and heavier than softwoods.

Softwoods used for firewood in the UK are mostly spruce, pine, fir and larch (There are several sub-species of each).

Softwood trees tend to be faster growing and the wood is less dense and lighter than hardwoods. The wood has more resin which may spit when burnt, so it is not really suitable for an open fire, but when dry, is perfect for stoves. The resin adds to the calorific value.

Hardwoods and softwoods have almost identical calorific value for a given moisture content and weight.

The difference to note is weight: the average density of UK hardwoods is about 700kg per solid cubic metre whilst the average density of softwoods is about 500kg per solid cubic metre. This means that you need about 1.35 cubic metres of softwood to be the equivalent of 1.0 cubic metre of hardwood.

So, there is no difference in calorific value (weight for weight, mc for mc) between hardwood and softwood, it’s just that you need about 30% more volume of softwood than hardwood for the same heat output.

Kiln Dried Logs

There are a few businesses kiln drying logs in the UK, but the majority of kiln dried logs sold in the UK are imported from Europe. Some of this is very good and of excellent quality and consistency. Clearly logs of this quality are more expensive than you would be paying your local log supplier.

Seasoned Logs

Trees should be felled over winter whilst the moisture content is lowest. They are then processed into logs and stored in open mesh log bags or wooden crates inside open sided barns where the natural movement of air dries them during summer months ready for use the next winter.

Beware of logs that are being processed on a just-in-time basis for sale immediately. Their moisture content is sure to be between 28% and 50%.

Fresh Felled Timber

Trees are felled over winter when the sap (water) within the tree is at its lowest. The moisture content over winter is usually between 30% and 50% so it is necessary to reduce the moisture content to around 20%.

Recently felled trees are hopeless for burning as the fire has to use lots of energy just to dry the wood before it will burn properly.

Wet firewood can be extremely damaging when mixed with coal. Most coal and smokeless fuel has a high sulphur content. When water from the wood combines with sulphur, then sulphurous acid forms on the cooler surfaces within your system leading to rapid damage of metals.

Damp wood burnt alone leads to soot deposits in the chimney, blackening of the stove glass and much more wood is required for the same level of heat.

Quality Assurance

After 200 years of burning fossil fuels in the UK, wood is at last moving back into mainstream use for space and water heating.

This is greatly encouraged by the Government’s Renewable Heat Incentive (RHI) that pays householders to produce renewable heat.

In order to maximise the calorific value of wood fuel, and therefore its effectiveness, it is essential that the supply is consistent in moisture content and size.

HETAS and Woodsure have just launched a Quality Assurance Scheme for biomass based on the Draft European Standard. Firewood log production can be assessed under this scheme and that will give customers confidence that their HETAS assured supplier consistently produces wood fuel to exacting standards required by modern biomass stoves and their ever more informed and discerning owners.

Burning fuel is all about calorific value, and in particular the cost in terms of pence per kilowatt hour (p/kWh). Given this figure you can compare value between fuel products and suppliers.

Wood Briquettes: Modern wood burning stoves and open fires work exceptionally well with wood briquettes. If you can buy good quality briquettes for a similar cost to firewood logs (p/kWh) then briquettes will give a hotter, longer, more controllable burn, be easier and cleaner to handle and will take up less space to store than logs. What’s more, most briquettes are made from softwoods and it is far better for the environment if we burn a sitka spruce tree than an oak tree.

Here are some of the more common sources of confusion:

One tonne builder’s dumpy bag: It’s not a tonne of wood you get, as some suppliers claim, more like 220kg if it’s hardwood dried to 20% moisture content, and it’s not “nearly one cubic metre”, more like 0.56/0.75 cubic metre.

Crate measuring 1m x 1m x 1.9m: That’s the outside measurement but you don’t get 1.9 cubic metres of firewood, more like 1.6 when you measure the internal stack.

Truck, pickup, trailer load: It’s open to interpretation as to how much you’re getting. It may be good value but it’s taking a lot on trust, so assess it carefully. At least there is no packaging, but now you have to carry and stack.

Seasoned for one/two years: Perhaps, but what is the moisture content (mc)? Under 20%mc and it is ready to burn now. Over 25% and the calorific value starts to plummet, and the steam to rise.

Burning damp or green wood is very bad for your stove and can cause the flue to tar up quickly.

With gas prices skyrocketing in the UK, many homeowners are looking for alternative ways to heat their homes that won’t break the bank. One option that’s gaining popularity is installing a wood burning stove or log burner. But are log burners actually cheaper to run than central heating powered by natural gas? Let’s take a look at the key factors.

Fuel Costs

The biggest factor when comparing costs is the price of the fuel itself. Natural gas prices have risen dramatically, with the energy price cap set to increase to over £3,500 per year for average usage. Hardwood logs on the other hand have seen much smaller price increases. A cubic metre of seasoned hardwood logs costs £75-120 delivered.

So, on fuel costs alone, wood comes in substantially cheaper than gas to generate the same amount of heat energy. However, the efficiency and running costs of the heating system also need to be considered.

Efficiency

A modern condensing gas boiler can be over 90% efficient at converting the energy in gas to heat. Some of the latest models even reach 98% efficiency. Wood burners are generally less efficient, with typical older models having 65-75% efficiency. This means more logs are needed to produce the same heat output. However, the latest ECO Design modern wood stoves can reach 85% efficiency or higher, so the efficiency gap is narrowing.

In terms of distribution, radiators do lose some heat into unheated rooms. But a wood burner’s heat is very concentrated in one area, with other rooms losing out. Strategic placement of the wood burner in a main living area that connects to other rooms can help distribute the warmth more evenly.

Installation and Running Costs

Adding a log burner or wood stove will require an upfront installation cost of £1,500-£4,000 including the unit, flue, and labour. A gas boiler replacement with a qualified engineer will cost £2,000-£3,000. Ongoing maintenance costs are low for gas boilers, aside from the annual service. Log burners and their flues need more frequent sweeping to remove ash buildup and creosote. This costs around £50-80 per sweep. Gas boilers only need electricity for the igniter and controls. The majority of wood burning systems do not need electric power at all.

With the right setup and use, a modern log burner can certainly save money compared to gas central heating based on current fuel prices. The savings will depend on:

– How much you use it – as a secondary heat source or a complete replacement
– Your home’s insulation and heat demand
– The efficiency of your particular appliance and heating system
– Local fuel prices and delivery costs

Wood burners do need more maintenance and have higher upfront installation costs. But with gas prices predicted to remain high, using logs in an efficient modern appliance looks an attractive option to cut home heating bills this winter. Just be sure to get your chimney swept regularly!

Additional Factors to Consider

Here are some other factors that can determine whether switching to a wood burning stove will save you money:

Home Insulation

An energy efficient, well insulated home will require less heating input overall. This makes the potential savings from wood fuel greater compared to an older, drafty building. Investing in insulation upgrades like loft and cavity wall insulation improves the economics.

Heat Demand

The size of your home and number of rooms that need heating will impact consumption. More heat demand means more fuel needed. A wood burner may struggle to meet the full needs of a large detached house. Additional radiators or underfloor systems may still rely on some gas.

Access to Wood Fuel Supply

Sourcing good quality, affordable logs is key. Those in rural locations may have better access to local log supplies. Delivery costs can be reduced. Urban residents may find sourcing and delivering wood fuel more expensive from national suppliers.

Environmental Impact

While wood is considered carbon neutral over its full lifecycle, burning logs does release particulate pollution. This needs to be weighed against the carbon cost of natural gas. Newer wood stoves have much lower particulate emissions to reduce the health impacts.

Household Size

More people in the home means more heating needed. Families may find it worthwhile to switch, whereas smaller households may not use enough fuel to achieve real savings. The hassle of storing and loading the stove also becomes more significant.

Log burners can certainly save money compared to gas heating based on current fuel costs. But the actual savings achieved depend on the home, heating demand, appliance efficiency and fuel supply logistics. Each household’s situation will determine whether wood burning can reduce their heating bills over the coming winter months.

In summary, given the extreme gas price rises seen in 2022, and predictions that prices will remain high this winter; installing a modern, efficient log burner looks an increasingly attractive option for UK households looking to reduce heating bills. For those with access to competitively priced wood fuel supply, and who take the time to use their stove efficiently, the potential savings over gas central heating could be substantial. While they require more maintenance and upfront cost, log burners can provide cheaper, renewable heat and reduce reliance on imported fossil fuels. For suitable properties and owners willing to adjust their heating habits, embracing the traditional log fire could prove a financial lifeline this winter.

In an effort to tackle air pollution, the UK government published its Clean Air Strategy 2019 this January. The document itself is a lengthy pledge to reduce the percentage of airborne pollutants across a variety of sectors by 2020 and 2030. It was inspired by recommendations made by the World Health Organisation and states that air pollution poses one of the greatest current risks to public health, as well as being extremely detrimental to the environment and, by extension, the economy.

Since the Clean Air Strategy 2019 was published, there have been a lot of misconceptions about what the new regulatory framework will mean for those wanting to burn open fires or heat their homes with woodburning stoves. Some media outlets have helped to create the impression that all open fires and stoves will be banned in the coming years. However, this is not the case. The government has absolutely no intention of banning the public from burning wood as part of its new air pollution strategy. It merely wants to restrict the types of fuel used in such situations to reduce the percentage of pollutants in our atmosphere.

According to a BBC report, pollution caused by wood or coal burned in the home contributes over twice as many harmful participates as industrial combustion and three times the volume caused by road transport. It is this excess that the new measures aim to curtail.

As part of the government initiative, only the sale of environmentally sound stoves will be permitted and clean fuel with a moisture content of less than 20 per cent must be burned. There will also be a greater drive to make sure people are only burning smokeless coal and low sulphur fuels.

The Clean Air Strategy identifies sulphur dioxide from coal as being one of the biggest threats to health associated with air pollution. It cites the London smog of 1952, attributing between 8,000 and 12,000 fatalities to the quantity of the pollutant in the metropolis. Whilst the regulations effect on the general fire-burning public will be minimal, the measures will certainly impact the sale of firewood from vendors such as petrol stations – renowned for flogging sacks of damp wood all year round. Instead, those wishing to buy firewood should head to a reputable supplier such as Carnethy Woodfuel for their fuel needs.

Therese Coffey, the UK’s Environment Minister, stated of the strategy prior to the publication of the Clean Air Strategy 2019: “While we will never be able to eliminate all particulate matter, by switching to cleaner fuels, householders can reduce the amount of harmful pollution to which they unwittingly expose themselves, their families and the environment, while still enjoying the warmth and pleasure of a fire.”

Get Ahead of the Game Now

There are loads of things you can do today to get yourself ready for the regulations detailed in the Clean Air Strategy 2019. Follow the guidelines below and the good habits you pick up will make the eventual transition an absolute breeze!

Use Ready-to-Burn Fuel from a Reputable Supplier

Always source your wood from a trusted supplier of firewood. As tempting as it might be to break down that old couch or bookshelf and save a few quid, you will be running foul of Clean Air Strategy regulations by doing so. It should go without saying that plastics should be avoided too. New regulations aside, who would want to sit breathing plastic fumes in their living room!?

Store Your Wood Correctly

It’s no good buying all that beautiful dry, regulatory-compliant wood if you’re not going to store it correctly. The best way to keep your wood in the best, ready-to-burn condition possible is by using a purpose-built log store. Such constructions range from the ultra-compact at £100 or less, right through to the most extravagant and grandiose, costing thousands. Which you go for will ultimately depend on the amount of wood you want to store, your budget, and the space limitations of your property. Of course, if you’re handy in the tool shed, you can always knock one up yourself too.

A great resource for those looking to buy a log store to keep their wood dry year-round is WhatShed. Check out their detailed listings and reviews here

Sweep Your Chimney

Sweeping your chimney at least once a year will prevent the build up of particulates that can contribute to air pollution and, in more extreme situations, chimney fires. Contact a qualified chimney sweep. They’ll not get rid of all that nasty build up but will likely give you other pointers on how to reduce your environmental impact when using your wood burner too.  https://whatshed.co.uk/log-store/

So, I Can Definitely Still Use My Stove, Right?

Yes, of course you can! You just need to make sure that the wood you burn in it is untreated and has less than 20 per cent moisture content and we all know, this burns best anyway! That said, if you were planning on buying a new wood burning stove, make sure it meets the minimum environmental requirements. The Department of Environmental and Rural Affairs (DEFRA) and the Stove Industry Alliance recommends using SIA Eco design Ready stoves, which are certainly exempt from the regulatory measures. 

What About My Open Indoor Fire?

The government has not commented specifically on open fires. However, DEFRA does acknowledge that they produce much more smoke than an efficient, modern wood burning stove. Until further word is given in relation to open fires, the applicable guidelines above should be followed.

The above information has been prepared by WhatShed who specialise in sheds and garden buildings. If you are looking to purchase a log shed then we would recommend having a look here